Jessica N. Velasquez Suzanne Chwala-Grant

Jessica N. Velasquez

From: [email protected] Sent: Wednesday, January 11, 2017 5:25 PM To: WMISHelpDesk Cc: Ken Griner Subject: ERP Application Number: 739949 (Email 2 of 2) Attachments: IV-VI from Ordinary Exemption - RMS.pdf

Please upload the attached document to application No. 739949.

Suzanne

Suzanne Chwala‐Grant Project Manager/Hydrologist David Cannon Well Drilling, Inc. P.O. Box 38 Parrish, FL 34219 Office: (941) 776‐1471 Fax: (941) 776‐0932 Cell: (941) 779‐4551 Email: [email protected]

1 IV. Conservation Plan and Maps

A. Conservation Plan – Description

B. Conservation Plan – Maps and Figure

Map – National Wetland Inventory (NWI) and FEMA Floodplain Data

Map – Area Topography/Contours

Map – Project Area DEM

Map – Project Specific Survey Elevations and General Flow Direction

Map – Project Conservation Plan

Figure – Typical Blueberry Row Cross Section

Resource Management Plan - Altos Rock, LLC CONSERVATION PLAN - DESCRIPTION Altos Rock, LLC

Altos Rock, LLC commits to the following conservation measures:

Nutrient Management – Fertilization will be based on IFAS and/or NRCS recommendations or according to the producer’s goals; whichever is lower.

Pest Management – Pest populations will be managed using Integrated Pest Management (IPM) techniques. The procedures used will prove the desirable level of pest control while minimizing the potential for leaching or runoff.

Micro Irrigation – A low volume, dual drip emitter irrigation system will be installed to efficiently apply water directly to the root zone to maintain adequate moisture within the desired range for optimum plant growth.

Overhead Sprinkler – A solid set overhead sprinkler system will be installed in order to protect the crop during frost freeze events.

Irrigation Water Management – The irrigation system will only be operated when necessary and timing of irrigation events are determined by current onsite conditions, data from local weather stations, onsite rain gauges and IFAS or NRCS recommendations. Irrigation events will occur in early morning or late afternoon hours when evaporation rates and winds are typically at their lowest. The overhead sprinkler system will be inspected during use to ensure coverage is sufficient and non-crop areas are not being irrigated. The efficiency of the drip irrigation system will be monitored to ensure adequate moisture is applied to the root zone.

Row Arrangement – The blueberry crop will be established within north-south rows at lengths that provide efficient and adequate water as well as erosion control.

Mulching – Pine bark mulch will be integrated into the top soil and used as the growing medium (substrate). The mulch beds will be covered with shade cloth which helps to control weeds and conserve water. Used mulch will be rolled or baled and removed according to local environmental regulations.

Cover Crop – A permanent vegetative cover will be maintained on the exposed middles to avoid erosion by wind and/or water. These areas will be fertilized, mowed and/or irrigated only as needed to maintain the cover. Planting of the vegetative cover will occur at NRCS or IFAS recommended seed rates and will typically be Bahiagrass or Bermudagrass.

Note: Please also see Section Nos. V and VI for additional conservation measures and BMPs. National Wetlands Inventory and Floodplain Limits Altos Rock, LLC

PSS1C Legend PFO1/3C WUP Boundary Field/Crop Area = 80 Acres Flood Zone A PSS1C National Wetland Inventory Wetlands: 50-Foot Buffer

PFO1C

PEM1C

PFO1C

80 Legend WUP Boundary 85

Field/Crop95 Area = 80 Acres 80

85 75

110 100

105

75 65

Image: 2014 Hardee County, FL 0 330 660 1,320 1,980 Scale: 1:10,000 Feet Data and images presented within this map are for informational purposes and not intended to - be used in lieu of official surveyed data. Digital Elevation Model (Labins) Altos Rock, LLC

Legend WUP Boundary Field/Crop Area = 80 Acres Existing Ridge/Divide

Legend WUP Boundary Flow Directions Field/Crop Area = 80 Acres Existing Ridge/Divide

49 49 49 48 47 46 45 50 50 49 49 49 47 44 50 49 48 46 45 50 50 50 50 50 47 46 50 49 48 46 50 50 45 50 50 44 43 51 50 49 47 50 51 43 49 51 51 48 47 51 51 51 51 44 49 50 51 51 51 51 47 50 49 45 51 46 50 49 43 50 52 51 50 47 44 51 45 52 52 48 50 52 42

46 51 49 52 42 51 47 45 43 49 52 52 52 52 50 46 49 50 44 45 51 47 52 52

51 48 51 51 51 51 51

42 52 43 49 49 50 51 51 49 49 51 50 47 49 51 50 50 50 50 49 46 45 44 50 50 48 51 50 47 42 49 50 50 51 49 49 44 51 49 48 43 50 49 48 49 49 47 46 50 49 45 41 48 49 49

42 48 46 43 48 50 50 49 47 45 50 48 42 49 50 50 48 48 44 48 50 48 48 49 50 48 47 46 40 49 45 47 49 47 49 47 41 40 47 48 47 47 47 44 43 48 48 45 47 49 46 44 42 40 49 49 48 49 46 43 48 47 46 44 47 49 46 48 49 43

48 41 47 47 45 42 44 43 43 42 47 48 48 46 48 47 45 43 46 49 44 47 49 49 48 49 47 46 44

47 41 45 44 43 42 42 47 48 48 42 46 42 40 46 47 48 44 42 42 42 47 43 41 46 44 41 46 46 47 47 42 41 41 41 47 47 46 45 44 43 46 41 46 46 45 43 46 45 41 40 45 43 41 40 45 45 44 44 44 39 45 45 45 43 40 44 43 43 43 40 44 42

Legend WUP Boundary Well Status, Use !H Existing, Irrigation /" Proposed, Irrigation "/ Proposed, Standby Field/Crop Area = 80 Acres Property: 25-Foot Setback

1 !H 2 4 /" "/

3 /"

Image: 2014 Hardee County, FL 0 165 330 660 990 Scale: 1:5,000 Feet Data and images presented within this map are for informational purposes and not intended to - be used in lieu of official surveyed data. NOTES: NOT TO SCALE * Row orientation will be North-South * Pink bark mulch will be integrated into top soil and beds covered with shade cloth * Drive middles will be maintained in permanent grass or vegetative cover * Please see Resource Management Plan for construction specifications and O & M Plan

Natural Ground

Data and images Typical Blueberry Row Cross Section presented within this map are for informational purposes and not intended Altos Rock, LLC to be used in lieu of official surveyed data. Hardee County, Florida V. Nutrient, Pest and Irrigation Water Management

A. Nutrient Management – Description and BMP Documentation IFAS: How to Calculate Fertigation Injection Rates for Commercial Blueberry Production (HS1197) NRCS: Nutrient Management Conservation Practice Standard (590) Fertilizing Blueberries in Pine Bark Beds; University of Georgia

B. Pest Management – Description and BMP Documentation IFAS: 2013 Florida Blueberry Integrated Pest Management Guide (HS1156) NRCS: Integrated Pest Management Conservation Practice Standard (595)

C. Irrigation Water Management – Description and BMP Documentation IFAS: Protecting Blueberries from Freezes in Florida (HS968) IFAS: Improving the Precision of Blueberry Frost Protection Irrigation (FE979) IFAS: Water Use in Establishment of Young Blueberry Plants (BUL296)

D. Additional Management – Description and BMP Documentation IFAS: Weed Management in Blueberry (HS90) NRCS: Precision Land Forming Conservation Practice Standard (462) IFAS: Cover Crops (SSAGR66)

Resource Management Plan - Altos Rock, LLC V. A. Nutrient Management – Description and BMP Documentation

Nutrient Management Description

IFAS: How to Calculate Fertigation Injection Rates for Commercial Blueberry Production (HS1197)

NRCS: Nutrient Management Conservation Practice Standard (590)

Fertilizing Blueberries in Pine Bark Beds; University of Georgia

V.A. NUTRIENT MANAGEMENT PLAN - DESCRIPTION Altos Rock, LLC

Objective: Creation of a nutrient management plan that’s built into a comprehensive conservation plan with compatible requirements.

The principal behind nutrient management is to provide adequate nutrients to the plant while having a positive effect on the surrounding natural environment (water, soil, etc.). The goal is to develop a nutrient management program that manages the “four R’s”: Right source of nutrients, Right time of application, Right rate and Right method of application. The four R approach will minimize the amount lost to runoff, leaching and/or volatilization and is economically viable. Development of the nutrient management program often starts with a soil (or substrate) analysis to determine the amount of nutrients contributing to the overall crop nutrient requirement (CNR). This information would be used as guidance in determining the amount of fertilizer needed. A listing of CNRs and other IFAS and NRCS reference materials are available online, within this Exemption Request, and available onsite.

Method, Form and Timing of Application:

• Fertigation will occur after initial planting and 1-inch of water has been applied to settle the substrate/soil as blueberry roots are shallow and fine textured. • Applications will be applied at a rate needed by the crop grown (CNR) and will not exceed the loading rate of the pine bark substrate. • From March 15 – November 1; young plants should be fertilized every 3 weeks. From November 2 – March 14; increase fertilizer application interval to 6 weeks. o Exceptions: Fertilization will not occur in any 3 week period if 1-inch of water is not available. • If soil K levels exceed 200ppm, then every other application, use ammonium sulfate instead of 12-4-8-2 or standard fertilizer and adjusts should be made to account for higher Nitrogen content. • Annual application of micronutrients should be considered and may be beneficial. • Fertilizer application rates can be decreased after plants are 3-5 years old, and should also be adjusted to current substrate/soil test levels.

Additional Improved or Best Management Practices (BMPs) The list below includes, but is not limited to, the BMPs to be implemented onsite: • Nutrient Management plan will be reviewed annually • Field records will be maintained for 5 years • Application equipment will be calibrated to apply within +/- 5% of the recommended rate. • Where practical, fertilizer will be applied in split applications. • Application timing will be based on stage of plant growth, substrate moisture content, weather and method of application. • Fertilizer containers will be disposed of according to local and state regulations. • Protective clothing will be used when appropriate during application to avoid unnecessary exposure. • Fertilizer will be stored where protected from rainfall and away from flammable materials. • Applications will not occur within setbacks or buffers to protect the surrounding environment. HS1197

How to Calculate Fertigation Injection Rates for Commercial Blueberry Production1 Guodong Liu, Jeffrey Williamson, Gary England, and Alicia Whidden2

Introduction correctly calculate fertigation injection rates and times and provides reference tables for checking injection rates and Florida’s commercial blueberry industry has increased times needed for a variety of production scenarios. significantly in both acreage and value, expanding from approximately 1,000 acres in 1993 to more than 4,000 acres in 2010 (Braswell 2010), and from $39 million in 2007 to Calculation of injection rate and $72 million in 2009 (Strange 2007). Per capita consumption time of blueberries has increased by 400% during the last decade Fertigation rate and time depend on the irrigation water (Braswell 2010). Florida produced approximately 17.7 flow rate and fertilizer application rate. To simplify the million pounds of fresh blueberries in the 2010 season. calculation, we will use nitrogen (N) fertilizer as an ex- However, Florida only contributed 4.2% of total U.S. fresh ample. For other nutrients, such as phosphorus, potassium, blueberry production, which was more than 416.5 million and the like, the principle is the same. For most cases, 0.1% pounds (USDA-NASS 2011). The value of blueberries of the irrigation flow rate is a proper injection rate (Burt, destined for processing has also increased. The total U.S. O’Connor, and Ruehr 1995). Six steps are needed to calcu- value of processed blueberries grew from $62.3 million in late the injection rate and time for fertigation if a solution N 2009 to $136.0 million in 2010 (USDA-NASS 2011). fertilizer is used. Florida’s subtropical climate allows for early blueberry Step 1: Determine the total amount of N needed for the production during a historically profitable marketing fertigation event. Calculate the total amount of N needed window. The industry is expected to continue to grow and by multiplying the farm size in acres by the N rate to be expand. To increase nutrient and water use efficiencies applied in pounds per acre. If you know your total linear and reduce nutrient leaching and environmental concerns, feet of bed and width of row spacing, the linear bed feet fertigation is recommended for commercial blueberry can also be used. For example, for a blueberry farm with a production. In fact, successful fertigation can enhance 4-foot bed and 8-foot row spacing, the actual linear feet of sustainability and maximize profitability for commercial bed per acre can be calculated as follows (Equation 1): blueberry enterprises. One of the key factors in fertigation is the correct calculation of fertilizer injection rate and time for the acreage. This publication helps blueberry growers

1. This document is HS1197, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date March 2012. Revised January 2015. Visit the EDIS website at http://edis.ifas.ufl.edu.

2. Guodong Liu, assistant professor; and Jeffrey Williamson, professor, Horticultural Sciences Department; Gary England, multicounty Extension agent III, UF/IFAS Extension Lake County; and Alicia Whidden, county Extension agent, UF/IFAS Extension Hillsborough County, UF/IFAS Extension, Gainesville, FL 32611.

Step 5: Calculate the injection rate. The injection rate is determined by dividing the irrigation water flow rate (e.g., 1,000 gallons per minute) by the dilution factor (from Step 4).

Step 6: Calculate the injection time. Injection time is determined by dividing the number of gallons of solution N fertilizer needed (from Step 3) for the fertigation event by the injection rate (from Step 5). Practical example We will use UAN-32 (32% N, 11.05 pounds per gallon) to apply 5 pounds N per acre to a 5-acre blueberry field with Figure 1. For a 4-foot irrigated bed within an 8-foot row spacing, the 8-foot spacing. The irrigation flow rate is 1,000 gallons per area that receives fertigation is half of the total, or “real estate,” area. minute and the target N concentration in the irrigation line Thus the actual bed area of the farm equals 50% of the farm area. is 150 ppm. To calculate the injection rate and time: However, all IFAS-recommended fertilizer rates are given on a “real estate” acre basis. The amount of fertilizer to apply is calculated based Step 1: Total N: 5 lb/acre N × 5 acres = 25 lb N on the entire area of the blueberry farm, regardless of the width of the bed to which the fertilizer is applied. Credits: Guodong Liu, UF/IFAS Step 2: Pounds of UAN-32: 25 lb N ÷ 0.32 = 78.1 lb UAN-32

Step 2: Calculate the total weight of liquid fertilizer needed Step 3: Gallons of UAN-32: 78.1 lb ÷ 11.05 lb/gal = 7.0 gal for fertigation. The total weight depends on both total N to be applied and the grade of the selected N fertilizer Step 4: Dilution factor: 0.32 × 1,000,000 ppm ÷ 150 ppm = solution. For instance, UAN-32 (urea-ammonium nitrate 2,133.3 solution, 32-0-0) contains 32% N by weight. The total weight of the fertilizer solution to apply is equal to the total Step 5: Injection rate: 1000 gal/min ÷ 2133.3 = 0.47 gal/min N needed (from Step 1) divided by the N concentration (0.32 in this example). For example, if you need 100 pounds Step 6: Injection time: 7.0 gal ÷ 0.47 gal/min = 15 min of N for a particular fertigation event, how much UAN-32 do you need? Divide 100 pounds by 0.32. You need 312.5 Therefore, in this particular case, 7.0 gallons of UAN-32 are pounds of UAN-32. needed for the fertigation event.

Step 3: Calculate the number of gallons of liquid N fertilizer. For different-sized blueberry farms with 1,000 gallons per This number is determined by the density of liquid N minute irrigation flow rate at target N concentration of 150 fertilizer. Every solution fertilizer has a density listed on ppm N and using UAN-32 as the N source, the correspond- the fertilizer label. For example, 1 gallon of UAN-32 weighs ing gallons of UAN-32 and injection time can be found in 11.05 pounds; thus, the density of this particular fertilizer is Table 1. Here, 150 ppm N is recommended because if the 11.05 pounds per gallon. The amount of fertilizer in gallons N concentration is too low, the plants may not be able to to apply is calculated by dividing the total weight of solu- get sufficient N. The fertilizer should not exceed 200 ppm tion fertilizer (from Step 2) by the density. in fertigation (Krewer and NeSmith 2012). This example uses UAN-32. Other soluble fertilizers can also be used in Step 4: Calculate the dilution factor. The dilution factor is fertigation. If using double drip tape per bed, the injection determined using the N concentration of the solution N time can be shortened by up to 50%.

How to Calculate Fertigation Injection Rates for Commercial Blueberry Production 2 For a 10-acre field using UAN-32 with a target N concen- Burt, C., K. O’Connor, and T. Ruehr. 1995. Fertigation. San tration of 150 ppm but with different water flow rates, the Luis Obispo: California Polytechnic State University. corresponding injection rate and time are shown in Table 2. Krewer, G. and D. S. NeSmith. 2012. “Bluberry Fertization Why is it important to calculate the fertigation rate cor- in Soil.” University of Georgia Ext. Fruit Publication 01-1. rectly? Because we need to make sure that blueberry plants Accessed January 19, 2015. http://www.smallfruits.org/ receive sufficient—but not excessive—nutrients. We must Blueberries/production/blueberryfert.pdf. avoid plant damage by not introducing too much salt at one time. We want to avoid over-applying fertilizer to save Strange, C. 2007. “FDACS Funds Pojects to Enhance money in fertilizer cost, thus maximizing profitability. We Florida Specialty Crop Competitiveness.” Florida Depart- should prevent or minimize potential nutrient contamina- ment of Agriculture and Consumer Services. Accessed tion of nearby water resources. October 31, 2011. http://www.freshfromflorida.com/ press/2009/03302009.html.

References USDA-NASS (United States Department of Agriculture- Braswell, B. 2010. “There’s Value in Growing Together: The National Statistics Service). 2011. “Noncitrus Fruits and Florida Blueberry Industry Continues to Take on the Many Nuts 2010 Summary (July 2011).” Accessed December Challenges Any Agriculture Endeavor Faces.” Growing Pro- 5, 2011. http://usda01.library.cornell.edu/usda/nass/ duce. Accessed October 31, 2011. http://www.growingpro- NoncFruiNu/2010s/2011/NoncFruiNu-07-07-2011.pdf. duce.com/article/18510/there-s-value-in-growing-together.

Table 1. Injection rate and time needed to apply 5 pounds of N per acre (in a 150 ppm N solution made from UAN-32 liquid fertilizer with 32% N) to a 1- to 100-acre farm with a 1,000-gallon per minute irrigation water flow rate Farm size Total N needed UAN-32 fertilizer needed Dilution factor Fertilizer injection Fertilizer injection rate time (acres) (lb) (lb) (gal) (gal/min) (min) 1 5 15.6 1.4 2133.3 0.5 3 2 10 31.3 2.8 2133.3 0.5 6 3 15 46.9 4.2 2133.3 0.5 9 4 20 62.5 5.7 2133.3 0.5 12 5 25 78.1 7.1 2133.3 0.5 15 Note: To prevent any nutrient contamination of nearby water sources and maximize profitability of commercial blueberry production, fertigation time should NOT be more than 15 minutes. If you have a blueberry farm with more than 5 acres, you may need to use a pump with large capacity to perform your fertigation.

Table 2. Calculation of injection rate if applying 5 pounds of N per acre (in a 150 ppm N solution made from UAN-32 liquid fertilizer with 32% N) to a 10-acre farm with 500-, 1,000-, 1,500-, or 2,000-gallon per minute flow rate from the pump Water flow rate Total N UAN-32 Dilution factor Injection rate Injection time (gal/min) (lb/acre) (lb) (gal) (gal/min) (min) 500 50 156.3 14.1 2133.3 0.2 60 1,000 50 156.3 14.1 2133.3 0.5 30 1,500 50 156.3 14.1 2133.3 0.7 20 2,000 50 156.3 14.1 2133.3 0.9 15

How to Calculate Fertigation Injection Rates for Commercial Blueberry Production 3 Field Office Technical Guide Section IV NATURAL RESOURCES CONSERVATION SERVICE CONSERVATION PRACTICE STANDARD

NUTRIENT MANAGEMENT

(Acre) CODE 590 CONDITIONS WHERE PRACTICE APPLIES This practice applies to all lands where plant nutrients and soil amendments are applied. This standard does not apply to one-time nutrient applications to establish perennial crops.

CRITERIA

General Criteria Applicable to All Purposes Plans for nutrient management must comply with all applicable Federal, state, and local laws, rules, and regulations. See the Reference Section for the specific laws.

Plans for nutrient management must be developed DEFINITION in accordance with requirements of the Natural Resources Conservation Service (NRCS) General Managing the amount (rate), source, placement Manual Title 190, Part 402, Nutrient Management; (method of application), and timing of plant technical requirements of the NRCS Field Office nutrients and soil amendments. Technical Guide (FOTG); procedures contained in the National Planning Procedures Handbook (NPPH), and the NRCS National Agronomy Manual PURPOSE (NAM) Section 503. • To budget, supply, and conserve nutrients for Impact to cultural resources, wetlands, and Federal plant production. and State protected species needs to be • To minimize agricultural nonpoint source determined prior to implementation of this practice. pollution of surface and ground water Any impacts need to be avoided or minimized to resources. the extent practical during planning, design and implementation of this conservation practice in • To properly utilize manure or organic by- accordance with established National and Florida products as a plant nutrient source. NRCS policy, General Manual (GM) Title 420-Part • To protect air quality by reducing odors, 401, Title 450-Part 401, and Title 190-Parts 410.22 nitrogen emissions (ammonia, oxides of and 410.26; National Planning Procedures nitrogen), and the formation of atmospheric Handbook (NPPH) FL Supplements to Parts 600.1 particulates. and 600.6; National Cultural Resources Procedures Handbook (NCRPH); and The National • To maintain or improve the physical, chemical Environmental Compliance Handbook (NECH). and biological condition of soil. A nutrient budget for nitrogen, phosphorus, and

potassium must be developed that considers all potential sources of nutrients including, but not limited to, green manures, legumes, crop residues,

Conservation practice standards are reviewed periodically, and updated if needed. To obtain the current version of this standard, contact the Natural Resources Conservation Service State Office, or download it from the electronic Field Office Technical Guide for your state.

NRCS, FL, November 2012 Nutrient Management 590 – 2 Field Office Technical Guide Section IV

compost, animal manure, organic by-products, DEP has determined specific conditions where the biosolids, waste water, organic matter, soil risk of phosphorus loss is low. These fields must biological activity, commercial fertilizer, and have a documented agronomic need for irrigation water. phosphorus; based on soil test phosphorus (STP) and UF/IFAS nutrient recommendations. Plans for nutrient management shall specify the source, amount, timing and method of application Soil, Manure, and Tissue Sampling and of nutrients on each field or area planned and is Laboratory Analysis (Testing). compatible with realistic production goals and Nutrient planning should be based on current soil, specify mitigation practices or efforts to minimize manure, and tissue (where used as a supplement) losses of nutrients and other potential test results developed in accordance with contaminants to surface and/or ground waters. University of Florida, Institute of Food and Enhanced efficiency fertilizers, used in Florida must Agricultural Sciences (UF/IFAS) guidance or comply with the definition by the Association of industry practice recognized by UF/IFAS. American Plant Food Control Officials (AAPFCO) Current soil tests are those that are no older than 3 and be accepted for use by Florida Department of years, but may be taken on an interval Agriculture and Consumer Services’ (FDACS) recommended by UF/IFAS or as required by Division of Agricultural Environmental Services Florida code (i.e., Biosolids, Chapter 62-640 Bureau of Compliance Monitoring has responsibility (F.A.C.). The area represented by a soil test must for verification of product guarantees, ingredients be that acreage recommended by UF/IFAS Soil (by AAPFCO definition) and label claims. Testing Procedure. For nutrient risk assessment policy and procedures Where a conservation management unit (CMU) is see Title 190, General Manual (GM), Part 402, used as the basis for a sampling unit, all acreage in Nutrient Management, and Title 190, National the CMU must have similar soil type, cropping Instruction (NI), Part 302, Nutrient Management history, and management practice treatment. Policy Implementation. Soil test analyses must be performed by The NRCS-approved nutrient risk assessment for laboratories successfully meeting the requirements nitrogen must be completed on all sites unless and performance standards of the North American Florida NRCS, with the concurrence of Florida Proficiency Testing Program-Performance Department of Environmental Protection (DEP) has Assessment Program (NAPT-PAP) under the determined specific conditions where nitrogen auspices of the Soil Science Society of America leaching is not a risk to water quality, including (SSSA) and NRCS, or other NRCS-approved drinking water. programs that consider laboratory performance The NRCS-approved nutrient risk assessment for and proficiency to assure accuracy of soil test phosphorus (Florida P-Index) must be completed results. Alternate proficiency testing programs must when: have stakeholder (e.g., FL DEP, NRCS State Staff, growers, and others) support and be regional in • Phosphorus application rate exceeds scope. UF/IFAS fertility rate guidelines for the planned crop(s), or The soil and tissue tests must include analyses pertinent to monitoring or amending the annual • The planned area is within a phosphorus- nutrient budget, e.g., pH, electrical conductivity impaired watershed (contributes to 303d- (EC) and sodicity where salts are a concern, soil listed water bodies), or organic matter, phosphorus, potassium, or other • The Florida NRCS and Florida DEP have nutrients and test for nitrogen where applicable. not determined specific conditions where Follow UF/IFAS guidelines regarding required the risk of phosphorus loss is low. analyses. A phosphorus risk assessment will not be required when Florida NRCS, with concurrence of Florida

NRCS, FL, November 2012 Nutrient Management 590 – 3 Field Office Technical Guide Section IV

Nutrient values of manure, organic by-products, If UF/IFAS does not provide specific guidance that and biosolids must be determined prior to land meet these criteria, application rates must be application. based on plans that consider realistic yield goals and associated plant nutrient uptake rates. Manure analyses must include, at minimum, total nitrogen (N), ammonium N, total phosphorus (P), Realistic yield goals must be based on historical or P2O5, total potassium (K) or K2O, and percent yield data, soil productivity information, climatic solids, or follow UF/IFAS guidance regarding conditions, nutrient test results, level of required analyses. management, and local research results considering comparable production conditions. Manure, organic by-products, and biosolids samples must be collected and analyzed at least Estimates of yield response must consider factors annually, or more frequently if needed to account such as soil quality, drainage, pH, salinity, etc., for operational changes (feed management, animal prior to assuming that nitrogen and/or phosphorus type, manure handling strategy, etc.) impacting are deficient. manure nutrient concentrations. For new crops or varieties, industry demonstrated Samples must be collected, prepared, stored, and yield, and nutrient utilization information may be shipped, following UF/IFAS guidance (See the used until UF/IFAS information is available. Livestock Waste Testing Laboratory web-site for Lower-than-recommended nutrient application sampling instructions: rates are permissible if the grower’s objectives are http://soilslab.ifas.ufl.edu/LWTL%20Home.asp or met. industry practice. Applications of biosolids, starter fertilizers, or pop- When planning for new or modified livestock up fertilizers must be accounted for in the nutrient operations, acceptable “book values” recognized budget. by the NRCS (e.g., NRCS Agricultural Waste Management Field Handbook) and the UF/IFAS, or Nutrient Sources. analyses from similar operations in the Nutrient sources utilized must be compatible with geographical area, may be used if they accurately the application timing, tillage and planting system, estimate nutrient output from the proposed soil properties, crop, crop rotation, soil organic operation. content, and local climate to minimize risk to the Manure testing analyses must be performed by environment. laboratories successfully meeting the requirements Nutrient Application, Timing and Placement. and performance standards of the Manure Testing Laboratory Certification program (MTLCP) under Timing and placement of all nutrients must the auspices of the Minnesota Department of correspond as closely as practical with plant Agriculture, or other NRCS-approved program that nutrient uptake (utilization by crops), and consider considers laboratory performance and proficiency nutrient source, cropping system limitations, soil to assure accurate manure test results. properties, weather conditions, drainage system, soil biology, and nutrient risk assessment results. Nutrient Application, Rates. Nutrients must not be surface-applied if nutrient Planned nutrient application rates for nitrogen, losses offsite are likely. This precludes spreading phosphorus, and potassium must not exceed on: UF/IFAS guidelines (SL-129) or industry practice when recognized by UF/IFAS • Soils when the top 2 inches of the soil are saturated from rainfall. Determination of nutrient rates must be based on crop/cropping sequence, current soil test results, Exceptions for the above criteria can be made for realistic yield goals, and NRCS-approved nutrient surface-applied manure and other organic by- risk assessments. products when specified conditions are met and adequate conservation measures are installed to

NRCS, FL, November 2012 Nutrient Management 590 – 4 Field Office Technical Guide Section IV

prevent the offsite delivery of nutrients. At a • other UF/IFAS recommended technologies that minimum, the following site and management improve nutrient use efficiency and minimize factors must be considered: surface or groundwater resource concerns. • Slope, • Organic residue and living covers, Additional Criteria Applicable to Properly Utilize • Amount and form of nutrients to be applied, Manure or Organic By-Products as a Plant and Nutrient Source • Adequate setback distances to protect local water quality. When manures and/or organic by-products are applied, and soil salinity is a concern, salt Additional Criteria to Minimize Agricultural concentrations must be monitored to prevent Non-point Source Pollution of Surface and potential crop damage and/or reduce soil quality. Groundwater The total single application of liquid manure: Planners must use the current NRCS-approved • Must not exceed the soil’s infiltration or water nitrogen, phosphorus, and soil erosion risk holding capacity assessment tools to assess the risk of nutrient and • Be based on crop rooting depth soil loss. Identified resource concerns must be • Must be adjusted to avoid runoff or loss to addressed to meet current planning criteria (quality subsurface tile drains. criteria). Technical criteria for risk assessments can be found in National Instruction (NI)-190-302 Do not apply waste/wastewater within 3 days of NRCS 190 Part 302 likely rainfall or during periods of frequent rainfall in a defined drainage way(s) that carries concentrated When there is a high risk of transport of nutrients, flow. Such material may be applied to newly conservation practices must be coordinated to constructed grass waterways if incorporated avoid, control, or trap manure and nutrients before immediately. they can leave the field by surface or subsurface Apply biosolids (sewage sludge) in accordance with drainage (e.g., tile). The number of applications USEPA regulations (40 CFR Parts 403 - General and the application rates must also be adjusted to Pretreatment Regulations for Existing and New limit the transport of nutrients to tile. Sources of Pollution and 503 (Biosolids Rule) and Biosolids, Chapter 62-640 (F.A.C.), If the biosolids Nutrients must be applied with the right placement, are septage from septic tanks, then follow in the right amount, at the right time, and from the Standards for Onsite Sewage Treatment and right source to minimize nutrient losses to surface Disposal Systems, Chapter 64E-6, (F.A.C.) and groundwater. The following nutrient use efficiency strategies or technologies must be Crop production activities and nutrient use considered: efficiency technologies must be coordinated to take advantage of mineralized plant-available nitrogen • slow and controlled release fertilizers to minimize the potential for nitrogen losses due to • nitrification and urease inhibitors denitrification or ammonia volatilization. • enhanced efficiency fertilizers • incorporation or injection Nitrogen and phosphorus application rates must be • timing and number of applications planned based on risk assessment results as determined by NRCS-approved nitrogen and • soil nitrate and organic N testing phosphorus risk assessment tools. • coordinate nutrient applications with optimum crop nutrient uptake When such assessments are completed, discuss • tissue testing, chlorophyll meters, and spectral the results of the assessment and analysis technologies recommendations with the producer during the development of the nutrient management plan.

NRCS, FL, November 2012 Nutrient Management 590 – 5 Field Office Technical Guide Section IV

For fields receiving manure and/or organic by- but not exceed, the recommended amounts of products, where phosphorus risk assessment nitrogen in any given year. results equate to LOW risk, additional phosphorus Manure may be applied at a rate equal to the and potassium can be applied at rates greater than recommended phosphorus application, or crop requirement not to exceed the nitrogen estimated phosphorus removal in harvested plant requirement for the succeeding crop. For fields biomass for the crop rotation, or multiple years in receiving manure and/or organic by-products, the crop sequence at one time. When such where phosphorus risk assessment results equate applications are made, the application rate must to MODERATE risk, additional phosphorus and not exceed the acceptable phosphorus risk potassium may be applied at a phosphorus crop assessment criteria, must not exceed the requirement rate for the planned crops in the recommended nitrogen application rate during the rotation. When phosphorus risk assessment year of application or harvest cycle, and no results equate to HIGH risk, additional phosphorus additional phosphorus must be applied in the and potassium may be applied at phosphorus crop current year and any additional years for which the removal rates if the following requirements are met: single application of phosphorus is supplying • a soil phosphorus drawdown strategy has been nutrients. implemented, and Regardless of nitrogen application rate used, do • a site assessment for nutrients and soil loss not apply manures on sites considered has been conducted to determine if mitigation vulnerable to off-site phosphorus transport unless practices are required to protect water quality. appropriate conservation practices, best • Any deviation from these high risk management practices, or other management requirements must have the approval of the activities are used to reduce the vulnerability to an Chief of the NRCS. acceptable level. Nitrogen Application Rates Heavy Metal Monitoring. When sewage sludge • When manure and/or organic by-products are (biosolids) is applied, the accumulation of potential used, match the nitrogen availability of the pollutants (including arsenic, cadmium, copper, planned application rates to plant uptake lead, mercury, selenium, and zinc) in the soil will be characteristics as closely as possible, taking monitored in accordance with the US Code, into consideration the timing of nutrient Reference 40 CFR, Parts 403 and 503, and application(s) in order to minimize leaching and Biosolids, Chapter 62-640 F.A.C. will be followed. atmospheric losses. There are several sources of crop uptake data that can be used (e.g., Additional Criteria to Protect Air Quality by Agricultural Waste Management Field Reducing Odors, Nitrogen Emissions and the Handbook (AWMFH), Chapter 6 and UF/IFAS Formation of Atmospheric Particulates research publications - Bahiagrass Fertilization). To address air quality concerns caused by odor, nitrogen, sulfur, and/or particulate emissions; the • Manure or organic by-products may be applied source, timing, amount, and placement of nutrients on legumes at rates equal to the estimated must be adjusted to minimize the negative impact removal of nitrogen in harvested plant biomass of these emissions on the environment and human not to exceed UF/IFAS recommendations. health. One or more of the following may be used: • When the nutrient management plan • slow or controlled release fertilizers component is being implemented on a • nitrification inhibitors phosphorus basis, apply manure or organic by- • urease inhibitors products at rates consistent with a phosphorus- • nutrient enhancement technologies limited application rate. In such situations, an • incorporation additional nitrogen application, from non- • injection organic sources, may be required to supply,

NRCS, FL, November 2012 Nutrient Management 590 – 6 Field Office Technical Guide Section IV

• stabilized nitrogen fertilizers 190.AGR.3, Precision Nutrient Management • residue and tillage management Planning (TN-190-AGR-3) • no-till or strip-till Soil test information should be no older than 1 year • other technologies that minimize the impact of when developing new plans. these emissions Use soil tests, plant tissue analyses, and field Do not apply poultry litter, manure, or organic by- observations to check for secondary plant nutrient products of similar dryness/density when there is a deficiencies or toxicity that may impact plant growth high probability that wind will blow the material or availability of the primary nutrients. offsite. Use the adaptive nutrient management learning When manure or organic by-products are applied process to improve nutrient use efficiency on farms to grassland, hayland, pasture or minimum-till as outlined in the NRCS’ National Nutrient Policy in areas, manage the rate, form, and timing of GM 190, Part 402, Nutrient Management. application(s) to minimize volatilization losses. PLANS AND SPECIFICATIONS When liquid forms of manure are applied with irrigation equipment, operators need to select The following components shall be included in the weather conditions during application that will nutrient management plan: minimize volatilization losses. (1) aerial site photograph(s)/imagery or site Additional Criteria to Improve or Maintain the map(s) and a soil survey map of the site; Physical, Chemical, and Biological Condition of (2) soil information including: soil type surface the Soil to Enhance Soil Quality for Crop texture, pH, drainage class, permeability, Production and Environmental Protection available water capacity, depth to water table, restrictive features, and flooding and/or Time the application of nutrients to avoid periods ponding frequency; when field activities will result in soil compaction. (3) current and/or planned plant production In areas where salinity is a concern, select nutrient sequence or crop rotation; sources that minimize the buildup of soil salts. (4) soil, water, compost, manure, organic by- CONSIDERATIONS product, and plant tissue sample analyses applicable to the plan; Soil test phosphorus levels should not exceed Florida approved soil test thresholds established to (5) realistic yield goals for the crop(s); protect the environment. See UF/IFAS publication (6) listing and quantification of all nutrient sources SL-129 for the soil test thresholds. and form; Use variable-rate nitrogen application based on (7) in accordance with the nitrogen and expected crop yields, soil variability, soil nitrate or phosphorus risk assessment tool(s), specify organic N supply levels, or chlorophyll the recommended nutrient application source, concentration. timing, amount (except for precision/variable Use variable-rate nitrogen, phosphorus, and rate applications specify method used to potassium application rates based on site-specific determine rate), and placement of plant variability in crop yield, soil characteristics, soil test nutrients for each field or management unit; values, and other soil productivity factors. (8) location of designated sensitive areas or Develop site-specific yield maps using a yield resources and the associated nutrient monitoring system. Use the data to further application restrictions and setbacks; diagnose low- and high- yield areas, or zones, and (9) guidance for implementation, operation, make the necessary management changes. See maintenance, recordkeeping; and Title 190, Agronomy Technical Note (TN)

NRCS, FL, November 2012 Nutrient Management 590 – 7 Field Office Technical Guide Section IV

(10) complete nutrient budget for nitrogen, If increases in soil phosphorus levels are expected phosphorus, and potassium for the plant (i.e., when N-based rates are used), the nutrient production sequence or crop rotation; management plan must document: (11) for manure applications, location of nearby • the soil phosphorus levels at which it is residences, or other locations where humans desirable to convert to phosphorus based may be present on a regular basis, and any planning, identified meteorological (e.g., prevailing winds • the potential for soil test phosphorus drawdown at different times of the year), or topographical from the production and harvesting of crops, influences that may affect the transport of and odors to those locations; • management activities or techniques used to (12) results of approved risk assessment tools for reduce the potential for phosphorus transport nitrogen, phosphorus, and erosion losses; and loss, • for Animal Feeding Operations (AFO’s), a (13) documentation establishing that the application quantification of manure produced in excess of site presents low risk for phosphorus transport crop nutrient requirements, and to local water when phosphorus is applied in • a long-term strategy and proposed excess of crop requirement; implementation timeline for reducing soil P to (14) when soil phosphorus levels are increasing, levels that protect water quality. include a discussion of the risk associated with phosphorus accumulation and a proposed OPERATION AND MAINTENANCE phosphorus draw-down strategy; The owner/client is responsible for safe operation (15) List all enhanced efficiency fertilizer products and maintenance of this practice including all that are planned for. equipment. Operation and maintenance addresses In addition, the following components must be the following: included in a precision/variable rate nutrient • Periodic plan review to determine if management plan: adjustments or modifications to the plan are • Document the geo-referenced field boundary needed. At a minimum, plans will be reviewed and data collected that was processed and and revised with each soil test cycle, changes analyzed as a GIS layer or layers to generate in manure volume or analysis, crops, or crop nutrient or soil amendment recommendations. management. • Document the nutrient recommendation • Fields receiving animal manures and/or guidance and recommendation equations used biosolids must be monitored for the to convert the GIS base data layer or layers to accumulation of heavy metals and phosphorus a nutrient source material recommendation in accordance with UF/IFAS guidance and FL GIS layer or layers. DEP guidelines. • Document if a variable rate nutrient or soil • Significant changes in animal numbers, amendment application was made. management, and feed management will • Provide application records per management necessitate additional manure analyses to zone or as applied map within individual field establish a revised average nutrient content. boundaries (or electronic records) • Calibrate application equipment to ensure documenting source, timing, method, and rate accurate distribution of material at planned of all applications that resulted from use of the rates. precision agriculture process for nutrient or soil • Document the nutrient application rate. When amendment applications. the applied rate differs from the planned rate, • Maintain the electronic records of the GIS data provide appropriate documentation for the layers and nutrient applications for at least 5 change. years.

NRCS, FL, November 2012 Nutrient Management 590 – 8 Field Office Technical Guide Section IV

• Records must be maintained for at least 5 U.S. Department of Agriculture, Natural Resources years to document plan implementation and Conservation Service. 2011. Title 190, National maintenance. As applicable, records include: Instruction (NI), Part 302, Nutrient Management Policy Implementation. Washington, DC. (1) soil, plant tissue, water, manure, and organic by-product analyses resulting in Biosolids, Chapter 62-640 Florida Administrative recommendations for nutrient application; Code (F.A.C.), http://www.dep.state.fl.us/legal/Rules/wastewater/6 (2) quantities, analyses and sources of 2-640.pdf nutrients applied; Standards for Onsite Sewage Treatment and (3) dates and method(s) of nutrient Disposal Systems, Chapter 64E-6,( F.A.C.) applications, source of nutrients, and rates http://www.doh.state.fl.us/environment/ostds/pdfiles of application; /forms/64e620061126.pdf (4) weather conditions and soil moisture at the Feedlot and Dairy Wastewater Treatment and time of application; lapsed time to manure Management Requirements, Chapter 62-670 incorporation, rainfall or irrigation event; (F.A.C.) (5) crops planted, planting and harvest dates, http://www.dep.state.fl.us/legal/Rules/wastewater/6 yields, nutrient analyses of harvested 2-670.pdf biomass, and crop residues removed, USEPA CAFO Rules (6) dates of plan review, name of reviewer, EPA - Concentrated Animal Feeding Operations - and recommended changes resulting from Final Rule the review, and USEPA 40 CFR Parts 403 and 503 (7) all enhanced efficiency fertilizer products (http://www.epa.gov/npdes/regulations/streamlin used. ing_part403.pdf) and (http://www.epa.gov/owm/mtb/biosolids/503pe/i Additional records for precision/variable rate sites ndex.htm must include: • maps identifying the variable application Agricultural Fertilizers, Chapter 576, F.S. source, timing, amount, and placement of all http://www.leg.state.fl.us/Statutes/index.cfm?App_ plant nutrients applied, and mode=Display_Statute&URL=0500- • GPS-based yield maps for crops where yields 0599/0576/0576.html can be digitally collected. Phosphorus Index, Exhibit 1, Chapter 9, Florida REFERENCES Agronomy Field Handbook Association of American Plant Food Control http://efotg.nrcs.usda.gov/references/public/FL/The Officials (AAPFCO). 2011. AAPFCO Official FloridaPhosphorusIndex080404Final.pdf Publication no. 64. AAPFCO Inc., Little Rock, AR. NRCS General Manual Title 450, Part 401.03 and U.S. Department of Agriculture, Natural Resources Title 190, Part 402 Conservation Service. 2010. Agronomy NRCS National Planning Procedures Handbook Technical Note, (TN) 190-AGR-3, Precision (NPPH) Nutrient Management Planning. Washington, DC. NRCS National Agronomy Manual (NAM) Section U.S. Department of Agriculture, Natural Resources 503. Conservation Service. 2011. Title 190, General NRCS Agricultural Waste Management Field Manual, (GM), Part 402, Nutrient Management. Handbook, Chapters 4, 6, and 11 Washington, DC.

NRCS, FL, November 2012 Fertilizing Highbush Blueberries in Pine Bark Beds

Gerard Krewer, Extension-Research Horticulturist John Ruter, Research-Extension Horticulturist

Physical Properties of Pine Bark decreases and nitrogen is tied up by microorganisms breaking down the cellulose. Rapid decay of organic Grower experiences have proven milled pine bark to matter in a blueberry substrate can result in shrinkage be an excellent growing substrate for southern high- which decreases aeration of the substrate. Sawdust has bush blueberries. Although milled pine bark shares a C:N ratio of about 1000:1, while pine bark has a ratio many characteristics with good blueberry soil, funda- of about 300:1. Both are considered to have a high C:N mental differences exist and need to be understood for ratio, but the saw dust is much more susceptible to rapid growth of young plants and high blueberry yields. rapid break down once nitrogen is added. This means Why has milled pine bark proven to be a successful that pine sawdust is best used as a blueberry amend- substrate (medium) for growing southern highbush ment mixed with sandy soil and not as a substrate for blueberries? high-density blueberry plantings. As the sawdust Internal pore space makes up 40-45 percent of a breaks down, the sandy soil provides aeration. Pine pine bark particle and assists in holding both water, bark also decomposes, but at a slower rate. Typically, a fertilizer and maintaining air space in the substrate. loss of 1 inch per year is seen in pine bark beds in Another 40 percent of the pine bark substrate is south Georgia. intraparticle pore space which also holds water, fertilizer and air. Approximately 20 percent of the pH of Pine Bark substrate is solid matter. In one study, fresh pine bark had a water holding capacity of about 13 percent by Pine bark should have a natural pH between 4.0 and volume, while aged pine bark held 21 percent water by 5.0, ideal for blueberries. Several sources disagree volume. Many pine bark substrates contain a signifi- whether the pH goes up or down slightly with decom- cant amount of sand from handling operations and this position. High pH irrigation water can raise the pH and can be beneficial in maintaining long term integrity of may require action by the grower. If the pH of pine the substrate. Water holding capacity is improved and bark increases above 5.0, use ammonium sulfate as a water infiltration rates are reduced by sand in the pine nitrogen source. Acidification of the irrigation water is bark, which promotes better wetting of the substrate. another option. Sulfuric acid is normally used for pH Air space equal to 20 to 30 percent of the volume pro- control of irrigation water. Many Georgia greenhouse vides adequate aeration and the drainage needed for an growers and longleaf pine nursery growers are acidi- extended rainy period. fying the irrigation water for their crops. Elemental Pine bark is high in lignin, an organic (carbon) sulfur can also be used to lower the pH, but apply a substance which is much more resistant to decay than modest amount (200 pounds per treated acre) and wait cellulose. Materials with a high cellulose (carbon) to several months to determine the extent of the pH nitrogen content will be decomposed rapidly by micro- change before applying more, if needed. At the 200 organisms once nitrogen is applied. Particle size pound per acre rate, sulfur can be applied over the top

1 on plants in the field. However, do not apply when the This creates a cap that seals off oxygen. Anaerobic leaves are wet. Iron sulfate can also be used to lower respiration can occur producing acetic acid the pH of the pine bark and supply iron. On plants (vinegar), phenolic and alkaloid compounds toxic already set in the field, use a maximum of ½ pound per to plants. The pH may drop as low as 2.0, which cubic yard of pine bark substrate or ½ pound per 54 causes nutrients (fertilizer salts) to be flushed from square feet. This is equivalent to 400 pounds per the pine bark. These can also be toxic. Check the treated acre if the pine bark is 6 inches deep. If the pH pH before planting. If low pH is a problem, wet of the pine bark is below 4.0 use urea as a nitrogen and aerate the pine bark. After three weeks the pH source. It is less acid-forming than ammonium sulfate. should return to about 4.0. Liming with dolomitic limestone can be conducted if 6. Mold in the bark thatrepels water. Pine bark in necessary, but has not been needed since most of the dry piles may develop high fungal populations deep well irrigation water in the South Georgia blue- recognized by clouds of spores when disturbed. berry belt is alkaline (pH above 7). Once spread out and irrigated, a mold (mycelia) grows rapidly which repels water. Newly set plants Pine Bark Problems may dry out and die. Frequent irrigation (5-6 times per day) may be needed to keep plant alive. Direct- Although pine bark has proven to be an excellent ing high pressure jets of water from a hose end substrate for southern highbush blueberries, there are a nozzle may break up the mycelial masses enough few odd problems for which growers need to be aware. to get water to the small plants. A surfactant can 1. Contamination of the bark with lime rock. This also be sprayed on the surface of the bark to assist has been a significant problem in Georgia. Lime with wetting. Wet pine bark before storing to avoid rock is often used to firm up the mud at saw mills. this problem. As pine bark is scooped up, some lime rock becomes mixed with the pine bark, raising the pH Pine Bark Particle Size and into the range where iron chlorosis occurs on Cation/Anion Exchange Capacity blueberries (above 5.3). 2. High manganese levels. Several growers have Milled pine bark with 70 to 80 percent of the par- experienced manganese levels in the blueberry ticles by volume within a range of 1/42 to 3/8 inch (0.6 plants as high as 2,000 ppm. When very high levels to 9.5 mm) in diameter, with the remaining particles of manganese accumulate in the plant, the leaves less than 1/42 (0.6 mm) is a good potting substrate. The may turn red and yellow and defoliate. Pine bark need for small particles is to provide better water and contains some manganese and manganese is more nutrient holding capacity by creating a large surface available at low pH. Another source of manganese area which provides cation exchange capacity. Cation is premium grade fertilizers and some fungicides. exchange capacity or CEC is a term used to describe Monitor manganese levels by tissue analysis. Do the attraction of cations (positively charged ions) in the not apply manganese containing fertilizers and fun- soil or pine bark to negatively charged sites on soil or gicides if manganese levels are excessive. pine bark particles. Many nutrients required by plants 3. Weed seeds. Some pine bark (especially old are positively charged and thus are attracted by these weed-covered piles) and pine bark which is con- negatively charged sites. Pine bark has a cation ex- taminated with dirt may contain weed seeds. This change capacity in the range of 10-13 milliequivalents has been an occasional problem in Georgia. per 100 cubic centimeters. As a comparison, course 4. Fire in pine bark storage piles. This is can be a sandy soils have a CEC of 5-15, silts soils 8-30 and problem with finely milled pine bark if piled too clay soils 25-50. Cations in the soil solution such as high. If temperatures reach over 150 degrees F, calcium, magnesium, ammonium nitrogen and potas- turn and moisten the pile. Don’t stack piles over 8 sium will be attracted to the surface of the pine bark feet in height. substrate and exchanged with other cations. The signi- ficance of CEC in practical terms is that it slows the 5. Low oxygen composting of pine bark (anaerobic rate of leaching of cations applied as fertilization respiration) causing very low pH. This can occur occurs. in pine bark when mold (mycelia) develops in a Anion exchange capacity or AEC of pine bark is band 24 to 30 inches below the surface of the pile. poor. Pine bark has little ability to hold anions such as

2 nitrates, phosphates or sulfates. Phosphates are Potassium: Blueberries do not tolerate high levels normally retained well in Georgia soils, but in pine of chloride, so do not apply high levels of potassium bark they leach out rapidly. chloride. However, potassium chloride can be used as part of a maintenance fertilizer program. The chloride Initial Conditioning of the will leach out with rainfall. Try to maintain at least 50 Pine Bark Substrate with Nitrogen ppm of potassium in the pine bark solution. Calcium: If you are using alkaline deep well water Because of the ability of fresh pine bark to absorb for irrigation, use a fertilizer with low calcium content. ammonium nitrogen and the fact that most milled pine Calcium fertilizers are rarely needed in blueberry pro- bark contains some wood which requires nitrogen for duction, but monitor via leaf and substrate samples. microbial degradation, growers should consider apply- Magnesium: This is a common deficiency in blue- ing nitrogen to fresh bark beds before planting. Aged, berries. Calcium and magnesium should be found in a composted pine bark will need less nitrogen applied ratio of not more than 2 to1 in the pine bark solution than fresh bark. Suggested amounts are ¼ pound per since they are in competition to enter the plant. High cubic yard for high quality, milled bark to up 1 pound calcium irrigation water combined with rapid leaching of nitrogen per cubic yard for pine bark containing a of magnesium often causes magnesium deficiency in significant amount of wood. blueberries. Dry fertilizers should contain a minimum If pine bark beds are 6 inches deep, then ¼ pound of of one and preferably two percent magnesium. nitrogen per cubic yard equals ¼ pound of nitrogen per Micronutrients: Dry fertilizers for blueberries 54 square feet of bed or 200 pounds per acre if broad- should generally contain a micronutrient package. cast. Since most high density systems have 75 percent Monitor the micronutrient levels via leaf samples and to 85 percent of the land area covered with pine bark, adjust your fertilizer accordingly. There have been then 150 to 170 pounds of nitrogen should be applied serious problems with excessive manganese levels on to the beds. The nitrogen used should be ammonium or some farms (see section above on pine bark problems). urea based. If the pine bark has a marginally high pH, Use fertilizers without manganese if levels are too above 5.0, use ammonium sulfate. Below 5.0 use urea high. Iron chelate and iron sulfate are good sources of since it is less acid forming. The nitrogen should be iron for blueberries. applied at least three months before planting and the beds kept moist. If the nitrogen is applied a month Dry Fertilizer Types before planting, use 50 pounds per acre. If high rates (600 pounds per acre) of nitrogen are needed to break Three types of dry fertilizer are used on blueberries down the wood in the very woody substrate, apply the in pine bark beds: granular soluble, slow release and nitrogen at least three months in advance of planting controlled release. In addition, liquid fertilizer for ferti- and keep moist. Test the substrate for high salt levels gation and foliar feeding are used. Each has advantages before planting (see section on monitoring). and disadvantages. Regular granular fertilizer is inexpensive, but must Fertilizer Sources for be applied every two to three weeks for best growth Blueberries in Pine Bark response. If applied too close to the plant in too large an amount, soluble granular fertilizer can cause burn- Nitrogen: Blueberries generally grow best with the ing. Materials containing slow release fertilizers are ammonium or slow release form of nitrogen. Urea is medium in price and reduce the number of fertilizer rapidly converted to the ammonium form of nitrogen applications to about four to eight per year in pine and can be used. Nitrate nitrogen can be used in small bark. There is a reduced chance of causing fertilizer amounts, but iron uptake and low pH maintenance is burn to young plants if improperly applied. Controlled assisted by the use of ammonium nitrogen. release materials are expensive, but reduce the number of fertilizer applications to two or three per year. Com- Phosphorus: Many types can be used. Diam- binations of dry fertilizers and liquid can also be used monium phosphate is a very good source and available to with great success. at low pH. Phosphorus leaches out of pine bark, but try to maintain at least 4 ppm of phosphorus in the pine bark solution.

3 Table 1. Characteristics of dry fertilizer types used in blueberries

Longevity in Applications Approx. Type Examples Pine Bark per Season Cost Comments

Granular soluble 8-8-8 Shot 6-8 $.12-.24 Read label; some do (regular fertilizer) 10-10-10 (2-4 weeks) lb not contain micro or (Super Rainbow, FFF, etc.) secondary nutrients. 12-4-8 (Big Buck, Gold Kist) Monitor nutrient levels by leaf analysis. If manganese or other micronutrient levels are becoming too high, use one without manganese or certain micronutrients. Slow release or Blends containing Medium 4 $.14-.50 Read label; some do partially slow ureaformaldehyde (UF) or (2-3 months) lb not contain micro or release isobutylidenediurea (IDBU) secondary nutrients. or sulfur-coated urea (SCU) Monitor nutrient levels or organic nitrogen as part by leaf analysis. If nitrogen source manganese or other Tristate 12-6-6 micronutrient levels are Growers Fert. 18-6-12 too high, use one Graco 13-6-6 (blueberry without manganese or special) certain micronutrients. Controlled release Meister 15-5-10 Long – varies 2-4 $.75- Usually contains micro (polymer or resin Sierrablen 18-7-10 with type (2-6 $1.00 lb or secondary nutrients coating) Osmocote 18-6-12 Plus months in but many may not be Georgia) listed; check with supplier. Monitor nutrient levels by leaf analysis. If manganese or other micronutrients are becoming too high, use a fertilizer without manganese or certain micronutrients.

Fertilizing Young Highbush Plants slow release fertilizer is used. This is based on manufacturer’s recommendations for a 1-gallon container. First year of planting Some growers are using several applications of controlled release fertilizer per year with regular fertilizer Young blueberry plants are easily burned by excess applied monthly. Scatter the fertilizer evenly over a fertilizer salts. For this reason, extreme caution must be circle about 12 inches in diameter the plant in the exercised if you are using a regular dry granular ferti- center. Increase amount of fertilizer as plants grow. lizer on young blueberry plants, especially rooted cuttings. Slow release or controlled release fertilizers Regular fertilizer in year one are recommended for this phase of production. Follow If you plant rooted cuttings or plug plants and manufacturer’s directions. Use the “low” or “medium” decide to use regular fertilizer, evenly apply about ½ rate for salt sensitive plants. teaspoon of premium grade (contains micronutrient) Rooted cuttings with controlled release 10-10-10 in a circle 12 inches in diameter, starting at and slow release fertilizer bud break and continuing every two to three weeks during the early part of the summer. This is equivalent If rooted cuttings or plug plants are set, typically to 30 pounds of nitrogen per acre if broadcast. As the about 1 teaspoon to 1 tablespoon of fertilizer per plant rooted cuttings grow to about a foot in height or if is applied at each application, with two to four appli- 1-gallon size plants are set, the rate can be increased to cations per year depending on if controlled release or a teaspoon per application and the diameter of the

4 circle increased to 18 inches. Apply every two to three This creates a higher demand for fertilization than weeks. This is equivalent to 27 pounds of nitrogen per plants growing in soil where moderate winter pruning acre if broadcast. is often the only pruning conducted. Also, since pine bark does not hold anions such as phosphate well, there Gallon size plants with controlled release is a need to apply phosphorus throughout the growing and slow release fertilizer season. If gallon size plants are set, use the recommenda- Research on fertilizing mature bushes in pine bark tions for a 3- to 5-gallon container. A typical program is very limited, but there is a large body of grower might be 1.5 ounces of 13-6-6 slow release fertilizer experience. One grower observation is the significant applied four times per year or 2-2.5 ounces of con- release of nitrogen from old pine bark beds. After the trolled release “8-9 month” 18-6-12 applied once. pine bark has been fertilized and aged for a number of Additional fertilizer from a regular, slow release or years, plants may not require as much nitrogen as shorter term controlled release material may be needed expected late in the season. Leaf nutrient levels and to finish the season, since “8-9 month” controlled growth should be monitored. release fertilizer is based on an average 70 degree F Many growers in Georgia and Florida are using a temperature and normally only lasts about five months premium grade (contains micronutrient and secondary in Georgia. Apply evenly in a circle about 24 inches in nutrients) 10-10-10, 12-4-8, or 18-6-12. Micronutrients diameter with the plant in the center. (boron, iron, manganese, zinc, etc.) and secondary nutrients (sulfur, magnesium, etc.) may be needed but Fertilizing two-year-old bushes some micronutrients such as boron and manganese may in pine bark beds reach toxic levels in some situations. Leaf nutrient If gallon plants were set and growing conditions levels should be monitored and fertilizer blends were favorable, a plant height of about 3 feet may be adjusted as needed. obtained by the start of year two. If you are using slow Typically about 100 to 220 pounds of actual nitro- release or controlled release fertilizer, spread the gen is applied per year, divided into six to eight appli- fertilizer over an area about 2 feet in diameter with the cations. A typical program with regular fertilizer plant in the center. The area of the circle in this case would be 150-200 pounds per acre of 10-10-10 or would be 7 square feet or 3.5 cubic feet (24 gallons) if 120-135 pounds per acre of 18-6-12 applied in mid- the pine bark is 6 inches deep. Follow manufacturer’s February, mid-March and early April in south Georgia. directions. A typical program may be 4 ounces of a Avoid application of nitrogen during harvest if the slow release material (such as 13-6-6) applied three plants look healthy and have adequate nitrogen in the times per year or 8 ounces of a 8-9 month controlled leaves based on leaf analysis. Make sure that plants release material (such as 18-6-12) applied once a year. have adequate potassium in the leaves at harvest. This In late summer an additional application of regular is an important element for fruit quality. However, fertilizer may be needed. excessive application of potassium will induce magne- Based on recent research from Florida by Wilber sium deficiency. Starting at hedging June 1, another and Williamson (2002), if you are using regular ferti- 150-200 pounds of 10-10-10 or 120-135 pounds per lizer, second year plants should receive about 2 tea- acre of 18-6-12 is applied every three to four weeks spoons (10.5 grams) of premium grade 10-10-10 or until early September in south Georgia. Allow the 12-4-8 applied to a circle 24 inches in diameter. This is plants to set terminal buds and harden off before winter equivalent to 30 pounds of nitrogen at each application or freeze injury may occur. Freeze injury can allow per acre if broadcast. Apply every two weeks during entry points for diseases such as stem blight. Some the period growth is desired. growers use foliar fertilizer or fertigation applied on an as needed basis in the fall, based on plant appearance Fertilizing bushes three years and older and weather. It can also be used as the sole method of In most high density southern highbush planting fertilizer application if the watering system is even. situations, bushes 3 years and older are considered mature and have filled their allotted space. Normally a severe rooftop hedging program is practiced, where the bushes are cut back to about 3 feet immediately after the harvest is finished (about June 1 in South Georgia).

5 Fertigation water will give 5 pounds of nitrogen in a 150 ppm solution. Fertigation can be used to supply all or part of the If your sprinklers apply 0.33 inches per hour, this is blueberry fertilizer requirement. Fertigation is an effi- about 9,000 gallons per hour. Dilute and inject the cient system in a high density planting, but wasteful in fertilizer over a period of about ½ hour. Irrigate with a low density system with overhead irrigation, since clear water for a few minutes after injection to wash only about 50 percent of the area has blueberry roots. off the plants, but do not flush out the fertilizer from Also note that your fertilization via fertigation will the pine bark. Repeat weekly as needed, but use a only be as even as your watering system. Typically balanced fertilizer if needed to phosphorus, potassium about 5 pounds of nitrogen per acre plus phos- and micronutrients. phorus and potassium (if needed) are injected each Contact the University of Georgia Extension Ser- week. vice via a county agent if you would like some help Avoid application of fertilizer during harvest in with the calculations. We will be glad to assist you. most cases. Since blueberries are a salt sensitive plant, determine the electrical conductivity of your fertilizer solution and dilute the fertilizer in enough water to Monitoring the Fertilizer create the proper solution. Your fertilizer supplier in the Pine Bark Substrate should have this information or we can obtain it for you. A maximum electrical conductivity of 0.75 Several methods can be used to check your fertilizer mMhos/cm (pronounced millimoles) is suggested for salt levels (electrical conductivity) in the pine bark. If salt sensitive plants such as blueberries. Typically this too low, growth will be reduced, if too high, root burn means the fertilizer should be diluted so that no more can occur. Samples can be collected and sent to the than 100 to 150 ppm of nitrogen is applied in the University of Georgia lab or a private lab as a “green- irrigation water at one time. This is calculated by the house/nursery” sample. This will give you nutrient following equation: levels and soluble salt levels in the pine bark. The following is a chart used in woody ornamental produc- lbs of fertilizer 100 x desired ppm (usu. 150 ppm) tion. mixture to add to = (% nitrogen concen. of fer. x 1205 100 gal of water Table 2. Range of nutrient concentration in satura- tion extraction method for soil-less media for As an example, if a 32% liquid nitrogen solution is used: optimal production of woody ornamentals during 0.39 lbs of 32% nitro-gen the growing season. [Method used by UGA lab] fertilizer solution/ 100 gal. 100 x 150 ppm 15,000 = = of irrigation water to form Parts per million (ppm) 32% x 1205 38,560 a 150 ppm nitrogen solution Element Insufficien Sufficient Excessiv t e To determine the amount of liquid to use: Nitrogen (nitrate) <39 40-139 >140 Since 32 percent nitrogen weighs 10.5 pounds per Phosphorus <3 4-13 >14 gallon, then divide 0.39 pounds of fertilizer by 10.5. Potassium <49 50-179 >180 The answer is 0.037 gallons of 32 percent nitrogen per Calcium <69 70-219 >220 100 gallons of irrigation water to equal 150 ppm of Magnesium <29 30-99 >100 nitrogen. Each gallon of 32 percent nitrogen contains 3.36 Electrical conductivity is a general measure of the pounds of nitrogen (10.5 pounds per gallon x .32 nitro- amount of fertilizer salts in the pine bark substrate. gen). If we want to apply 5 pounds of nitrogen per acre, You can purchase your own electrical conductivity divide 5 by 3.36 (number of pounds of nitrogen in a (EC) meter and use the “pour through” method to gallon of 32 percent nitrogen) = 1.49 gallons of 32 determine if the fertilizer salts are present in the percent nitrogen. To make a 150 ppm solution of the 32 substrate. (See http://pubs.caes.uga.edu/caespubs/ percent nitrogen, divide 1.49 gallons by 0.037 gallons horticulture/solublesalts.html) Suggested EC levels for = 40.27. Multiply times 100 gallons to get the number blueberry pine bark substrate are .50-.75 mMhos/cm. of gallons of irrigation water to add. The answer is 1.49 gallons of nitrogen diluted in 4,027 gallons of

6 Monitoring Leaf Nutrient Levels Selected sources of information and additional reading: Growers should monitor leaf nutrient levels at least Benson, R. R. 1999. Fertilizer technology. In: Landis, once a year. Traditionally this has been done in July T.D; Barnett, J.P., Tech. Coords. National Pro- and early August on rabbiteyes, but a better time for ceedings: forest and conservation nursery associa- southern highbush would be just prior to hedging in tions-1998. Gen. Tech. late May or early June. In this way, fertilization could be adjusted for the main summer and fall growth Rep. SRS-25, USDA, Asheville, N.C. flushes. Collect a double fist full of leaves from the Bilderback, T., undated. Managing container sub- mid-portion of the 20 shoots on 20 plants and place in a strates. N.C.S.U. paper bag. Take to your county extension office. http://www.ces.ncsu.edu/depts/hort/nursery/cultura Recently, high levels of manganese have been found in l/cultural_docs/substrates/managing_container_sub some high density plantings in Georgia. It is suspected s.pdf. that the source of the manganese is the fertilizer. If so, Bilderback, T. undated. Pine bark storage and handling. change to a fertilizer with little or no manganese. N.C.S.U. http://www.ces.ncsu.edu/depts/hort/nursery/cultura Suggested foliar nutrient levels for highbush l/cultural_docs/substrates/storage_hand.html. blueberry leaves. Halbrooks, M.C. 1990. Nutrition of container and Deficient Excessiv field-grown nursery crops. Clemson Univ. Coop. Element (below) Min. Max. e (above) Ext. Ser., Ext.Bulletin 138. Nitrogen 1.70% 1.80 2.10 2.50 Ingram, D.L., R.W.Henley, and T.H.Yeager. 1993. Phosphorus 0.10 0.12 0.40 0.80 Growth media for container grown ornamental Potassium 0.30 0.35 0.65 0.95 plants. Univ.of Fla. Bulletin 241. Calcium 0.13 0.40 0.80 1.00 Greef, Mark. 2005. Fine tuning southern highbush Magnesium 0.08 0.12 0.25 0.45 blueberry fertilizer programs. Proc. of the 12 th Sulfur 0.10 0.12 0.20 NA Biennial Southeast Blueberry Conference, Savannah, Ga. p.75-87. Manganese 23 ppm 50 350 450 Iron 60 60 200 400 Obreza, T.A., J.G. Williamson, R.L. Darnell, and P.M. Zinc 8 8 30 80 Lyrene. 1997. Performance of a young southwest Copper 5 5 20 100 Florida non-dormant blueberry planting. Proc. Fla. State Hort. Soc. 110: 175-177. Summary Ruter, J.M. 2001. Forest resources: containerized longleaf pine seedling production. 2001. Quality Growing southern highbush blueberries in pine bark control and nutrient management. www.bugwood. has been a successful and increasingly important meth- org/container/ruter.html. od of production. Fertilizing blueberries in pine bark is Wilber, W.L., and J.G.Williamson. 2002. Effects of similar to fertilizing in soil, but major differences are nitrogen fertilization on young southern highbush present that growers need to understand. blueberries grown in pine bark media. Poster presented at SR-ASHS, 2002.

7 Bulletin 1291 Reviewed February 2012

The University of Georgia and Ft. Valley State University, the U.S. Department of Agriculture and counties of the state cooperating. Cooperative Extension, the Uni- versity of Georgia College of Agricultural and Environmental Sciences, offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, gender or disability.

An Equal Opportunity Employer/Affirmative Action Organization Committed to a Diverse Work Force V. B. Pest Management – Description and BMP Documentation

Pest Management Description

IFAS: 2013 Florida Blueberry Integrated Pest Management Guide (HS1156)

NRCS: Integrated Pest Management Conservation Practice Standard (595)

V.B. PEST MANAGEMENT PLAN - DESCRIPTION Altos Rock, LLC

Objective: Creation of a pest management plan that’s built into a comprehensive resource management plan with compatible requirements.

Pest management involves a site specific combination of pest prevention, pest avoidance, pest monitoring, and pest management strategies. The overall goal is to reduce populations of target organisms to acceptable levels while minimizing contamination of soil, water and effects on non-target organisms (pollinators and other beneficial species) through the safe and economic use of pesticides. Pest management can also be achieved through using a combination of chemical and biological controls along with other BMPs, also known as Integrated Pest Management (IPM). IPM can improve overall pest control while minimizing the amount of chemicals applied, provide more economical crop production and reduce potential hazards to humans and environment. IPM can be achieved through the use of resistant plant varieties, improved management, biological controls and selective use of synthetic pesticides.

Improved or Best Management Practices (BMPs) The list below includes, but is not limited to, the BMPs to be implemented onsite:

• Pesticide use will be based on the presence of a pest that causes an economic threat to the crop • Pesticides will be applied according to IFAS recommendations for the specific test • Pesticides and diluents will be measured accurately to ensure the correct volumes and concentrations are produced • Label and Material Safety Data Sheet (MSDS) instructions will be followed and protective clothing will be used when appropriate. • Application equipment will be calibrated to apply within +/- 5% of the recommended rate. • Chemical mixing will occur at least 100 feet from wells or surface water bodies • Application equipment will be washed and stored in accordance with state and federal regulations. • Pesticides and containers will be handled, applied and disposed of according to manufacturer’s recommendations and/or local and state regulations. • Pesticides will not be applied near buffers when practical

HS1156

2013 Florida Blueberry Integrated Pest Management Guide1 Jeffrey G. Williamson, Philip F. Harmon, Oscar E. Liburd, and Peter Dittmar2

This publication was adapted for Florida from the Southeast safety and pest control standards indicated by experimental Regional Blueberry Integrated Management Guide, available data. at http://www.smallfruits.org/SmallFruitsRegGuide/Gui des/2006/12Jan06BlueberrySprayGuide.pdf. Thus, major This publication is intended for use only as a guide. Specific contributions were made by the original editors: Gerard rates and application methods are on the pesticide label, Krewer, Phil Brannen, Mark Czarnota, Dan Horton, Paul and these are subject to change at any time. Always refer to Guillebeau, and Paul Sumner (University of Georgia); Bill and read the pesticide label before making any application! Cline, Hannah Barrack, Katie Jennings, Wayne Mitchem, The pesticide label supersedes any information contained and David Monks (North Carolina State University); Frank in this guide, and it is the legal document referenced for Hale and David Lockwood (University of Tennessee); and application standards. Powell Smith and Bob Bellinger (Clemson University). Pesticide Emergencies Additional contributions by Allen Straw (Virginia Tech Poisonings: 1-800-222-1222 University), Scott Nesmith and Harald Scherm (University of Georgia), John Meyer (North Carolina State University), This number automatically connects you with a local Steve Bost (University of Tennessee), and Blair Sampson Poison Control Center from anywhere in the United States. (USDA/ARS Small Fruit Res. Station, Poplarville, MS). Pesticide spills or other emergencies: 1-800-424-9300 (24 Recommendations are based on information from the hours) CHEMTREK. manufacturer’s label and performance data from research and Extension field tests. Be prepared—visit www.chemtrek.com now for a listing of the information you will be asked to provide in a chemical Because environmental conditions and grower application spill emergency. methods vary widely, suggested use does not imply that performance of the pesticide will always conform to the

1. This document is HS1156, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date March 2009. Revised March 2013. Visit the EDIS website at http://edis.ifas.ufl.edu.

2. Jeffrey G.Williamson, professor, Horticultural Sciences Department; Philip F. Harmon, associate professor, Plant Pathology Department; Oscar E. Liburd, professor, Entomology and Nematology Department; and Peter Dittmar, assistant professor, Horticultural Sciences Department, Institute of Food and Agricultural Sciences, University of Florida Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition. All chemicals should be used in accordance with directions on the manufacturer’s label. Use pesticides safely. Read and follow directions on the manufacturer’s label.

• Interpreting Pesticide Label Wording (http://edis.ifas.ufl. In high-density bark beds, Ridomil Gold® EC also provides edu/pi071) good control of Pythium and Phytophthora root rots; however, using Ridomil Gold® EC in field plantings is very • Toxicity of Pesticides (http://edis.ifas.ufl.edu/pi008) expensive and difficult since the product has to be taken up by the roots for activity. Where possible, rotating Ridomil Sprayer Calibration: Sprayer calibration is very important. Gold® EC and phosphites is a good resistance-management Sprayers should be calibrated often to guard against ac- practice. Do not exceed label recommendations. cidentally using excess pesticides because of nozzle wear, speed increases, and other calibration problems. Failing to Postestablishment calibrate often costs money, may cause crop damage, and is unsafe. Blueberry gall midge – The blueberry gall midge is a tiny fly whose larvae feed on vegetative and floral buds. On rab- • Calibration of Herbicide Applicators (http://edis.ifas.ufl. biteye cultivars, the blueberry gall midge occurs frequently, edu/wg013) but it normally only causes economic levels of damage on susceptible cultivars. Blueberry gall midge can become a • Calibration of Airblast Sprayers (http://edis.ifas.ufl.edu/ major problem on some rabbiteye cultivars. Feeding injury ae238) destroys floral and vegetative buds before the bud scales open in the spring. In southern highbush blueberries Pesticide Calibration Formulas and Information http://edis. (SHB), blueberry gall midge is observed less frequently ifas.ufl.edu/wg067 than on rabbiteye, but SHB may show symptoms on new growth. Gall midges lay eggs on warm winter days and at Blueberry Integrated Management any time during the growing season when the plants are making new flushes of growth. For control, apply Delegate® Guide (Insect and Disease Control) or diazinon (if labeled for use on your site) as needed for Establishment gall midge between flower bud stages 1 and 2, when the Root rots – Blueberry root rots can be particularly prob- most mature buds first show slight scale separation. Repeat lematic immediately after transplanting and until plants sprays during warm spells if necessary. Bud scale separation are well established. Even in well-drained soils, root rots may occur as early as 15 December in north Florida. In have been observed in bark-amended beds, and root rots rabbiteye, ‘Premier’ is often particularly attractive to the gall are particularly damaging in high-density bark beds, even midge and is a good sentinel variety to monitor. Gall midge when using new bark. Though cost is an issue, replanting sprays can also suppress a prebloom thrips population. into old bark (high-density plantings) is not a good prac- Flower thrips – These are small insects (1/16 of an inch tice; disease-causing organisms build up in the bark, and in length) with yellowish to orange coloration and fringed they can make reestablishment very difficult. It is recom- wings. Flower thrips damage blueberry flowers in two ways. mended that phosphite-containing materials (Aliette®, Larvae and adults feed on all parts of the flowers, including ProPhyt®, Agri-Fos®, etc.) be used on nonbearing plants after ovaries, styles, petals, and developing fruit. This feeding establishment (for bedded and high-density bark plant- damage can reduce the quality and quantity of the fruit. ings). These materials are applied to leaves; therefore, leaf

2 Females damage the fruit when they lay their eggs inside Ant baits work best when the soil is moist but not wet. flower tissues. The newly hatched larvae bore holes in the Active ant foraging is essential. Ideally, temperatures should flower tissues when they emerge. White, blue, and yellow be warm and sunny. Avoid applying ant baits when condi- sticky traps can be used to monitor thrips. White traps are tions are expected to be cold, overcast, rainy, or very hot. preferred over blue and yellow because the thrips show up Individual mound treatments are most effective when used best against a light background and because the white traps as-needed for the occasional colony that survives broadcast do not attract as many beneficial insects as yellow traps. treatments. Mound treatments using insecticide baits Another technique for monitoring thrips involves gently should be applied in a circle 3–4 feet from the mound. Do tapping the flowers and allowing the thrips to fall onto not disturb mounds or place bait directly on top of mounds. a white sheet of paper below for counting. An economic injury level (EIL), the lowest number of thrips that can Mummy berry – Mummy berry is currently not identified cause economic damage in blueberries, has been developed as an important disease of southern highbush blueberry for two popular rabbiteye cultivars, ‘Tifblue’ and ‘Climax’. in Florida. The disease is a major issue in production areas During bloom, when thrips numbers reach approximately north of Florida. Florida growers concerned about potential 68 thrips per trap for ‘Tifblue’ and 75 thrips per trap for mummy berry problems are encouraged to contact county ‘Climax’ in a week, insecticide applications should be Extension for diagnostic confirmation and additional considered. It is recommended that growers use Delegate® information. WG at 6 oz. per acre to manage flower thrips populations in Florida blueberries (rabbiteye and southern highbush). Phytophthora root rot – Root rot is generally a problem of low-lying, poorly drained sites. To avoid root rot, provide Blueberry bud mite – The blueberry bud mite is an eri- adequate drainage by constructing raised beds before ophyid mite so tiny (1/125 inch long) that it cannot be seen planting. Site selection and/or proper bedding operations without magnification. Blueberry bud mite is an occasional are essential cultural practices for disease control. Treat- pest in well-established blueberries in Florida. Bud mite ment with fungicides is not effective for reversing root injury is often confused with frost damage and may become rot damage on plants with severe symptoms. Preventative more visible in late spring. In early spring, infested plants fungicide treatments in pine bark beds and poorly drained exhibit stunted, succulent, fleshy, closely packed, reddish sites may be warranted since the beds are often saturated rosetted buds, which may dry up and often fail to open. with water either by irrigation or rainfall. Bloom on infested plants is reduced. Affected berries are small and rough and may have small, reddish pimples or blisters on the fruit surface. Sanitation by aggressive, timely pruning of infested branches can be helpful. Mechanical topping (mowing off old fruiting twigs) immediately after harvest greatly reduces bud mite incidence the following year. Never propagate from bushes that may be infested with blueberry bud mite. Horticultural oil applications immediately after harvest aid in control.

Imported fire ants – Ant baits employed in early spring as a broadcast treatment usually eliminate most but not all fire ant mounds within treated areas. Under high ant pressure, treating a second time in the fall provides better fire ant control. Most ant baits are slow acting and require up to 8 weeks to control active mounds. Worker ants must be attracted to baits so that they will carry the baits back to their colonies. Most ant baits interfere with reproduction, causing a gradual colony die-off. Extinguish® Professional Fire Ant Bait (0.5% methoprene) is labeled for use on all crop land sites. It is effective but somewhat slower acting than Esteem® Ant Bait (0.5% pyriproxyfen).

3 Commonly recognized stages of flower bud development for southern highbush blueberry

Figure 3. Flower bud stage 3 Credits: Mark Longstroth (Michigan State University Extension)

Figure 1. Flower bud stage 1 Credits: Jeff Williamson

Figure 4. Flower bud stage 4 Credits: Mark Longstroth (Michigan State University Extension)

Figure 2. Flower bud stage 2 Credits: Jeff Williamson

4 Figure 5. Flower bud stage 5 Credits: Mark Longstroth (Michigan State University Extension)

Figure 7. Flower bud stage 7 Credits: Jeff Williamson

Figure 6. Flower bud stage 6 Credits: Jeff Williamson

5 Comments Apply 1/4 pt./1000 linear feet of row (3.6 pt. per acre per acre (3.6 pt. of row linear feet 1/4 pt./1000 Established plantings: Apply start in the plants growth before the row band over basis) in a 3-foot broadcast the spring. An or after at planting. rate) (broadcast per acre 3.6 pt. New plantings: Apply than 0.9 gal. Do not apply more is recommended. the row 18-inch band over bear harvestable plants fruit, duringbefore the 12 months broadcast per acre one both new and established plantings, For result. may or illegal residues for with periods most favorable coincide be made to may additional application development. rot root Oil may be applied dormant or delayed dormant. Apply as needed for scale as needed for Apply dormant. be applied dormant or delayed Oil may 85°F or exceed expected to are Do not apply oil when temperatures infestations. of lime-sulfur. Do not use within 14 days than 40°F within 24 hours. be lower fall. Apply on sunny days when the soil temperature is at least 60°F and the soil is at when the soil temperature days on sunny Apply fall. work.to weeks Do not make 4 Allow acting slow but effective. Baits are is moist. reapply if heavy, to need May for 7–10 days. other imported treatments ant fire within 7 days. rains occur flooding Caution: Extinguish® baits with methoprene plus hydramethylnon Extinguish® plus hydramethylnon Caution: baits with methoprene land. or duringof the day the heat Application land. use on crop not labeled for are the effectiveness is expectedwill reduce within 6 hours of application when rain be may applications repeat of this product. Inheavy infestation, areas necessary after the initial application. 10–12 weeks diazinon within 5 days of bloom because its residues may injure pollinators. injure may of bloom because its residues diazinon within 5 days to WG is toxic Delegate® gall midge and/or thrips. bloom for needed just before to nontoxic dry it is thoroughly bees until it is relatively (3 hours), but thereafter during evening WG should be applied in early morning or late Delegate® bees. bloom. plants 1 day before harvest to discourage ants from foraging on the plants. This This on the plants. foraging from ants harvest discourage to before 1 day plants postharvest Rely on aggressive off the plants. get ants to treatment is a stopgap these pests in blueberries. to suppress controls imported ant fire disturbing ants. avoid to gently Apply each mound. within 24 hours of bloom. not apply malathion (PHI) interval dormant) Postharvest Postharvest than delayed than delayed 4 h 0 days use on crop is legal for Bait (0.5% methoprene) Ant Fire Extinguish® Professional 4 h 3 days near bloom and should be applied as of choice WG is the material Delegate® 12 h 1 dayto be applied May rescue treatment. foliar Malathion is a modestly effective (REI) entry interval Restricted ++ +++ +++ ++++ 24 h 7 days Do not apply early gall midge sprays. for of choice Diazinon is the material ++++ 12 h 24 h again in the if needed, Bait should be applied during the spring Ant and, Esteem® ++++ 12 h 1 day Do 2 of bud development. stage 1 to gall midge at be applied for Malathion may +++++ 4 h 12 h (no later +++++) to most = to (Least = + (Least Effectiveness Effectiveness 1 pt. 1 pt. 2 pt. 6 oz. 3.6 pt. ++++ 48 h 0 days mound) mound) of water 1–1.5 lb. 1–1.5 lb. per acre 1.5–2.0 lb. 1.5–2.0 lb. (3–5 tbsp./ (3–5 tbsp./ (3–5 tbsp./ (2–4 tbsp./ water/acre water/acre Amount of Amount 1000 sq. ft.) 1000 sq. formulation formulation 1 pt./100 gal.1 pt./100 ++++ 24 h 7 days and 6 inches around mixture over of diluted apply 1 gal. Slowly Mound drench. 2 gal./100 gal. gal. 2 gal./100 or 2 fl. oz./1 gal. oz./1 gal. or 2 fl. EC) EC) Bait) 4EC) only. AG500) AG500) options Diazinon (Diazinon (Diazinon Malathion Malathion (70 second) (70 second) Mefenoxam Mefenoxam (Extinguish® Methoprene Methoprene Pyriproxyfen Pyriproxyfen (Esteem® Ant Ant (Esteem® (Malathion 57 (Malathion 57 Ant Bait 0.5%) Ant Delegate® WG Delegate® Prebloom use Prebloom (Ridomil Gold® Professional Fire Fire Professional ants Scale Superior oil root rot root Phytophtora Phytophtora Imported fire Pest/problem Management Gall midge Diazinon Table 1. Management strategies for pest and disease problems of dormant blueberry pest and disease problems for plants 1. Management strategies Table

6 Comments made before alternating with fungicides that have a different a different have that with fungicides alternating made before of applications mode of action. than four Do not apply more year. per crop per acre Pristine® Apply per year. per acre applications than four Do not make more product has been reported make This to 14-day 8- to at intervals. mix Tank when used alone during bloom. severe more ripe rot this problem. help prevent Indar® to with Captan thereafter it is relatively nontoxic to bees. Entrust® should be Entrust® bees. to nontoxic it is relatively thereafter during bloom. evening applied in early morning or late gall midge and/or thrips. Delegate® WG is toxic to bees until it is bees until to WG is toxic Delegate® gall midge and/or thrips. nontoxic drythoroughly it is relatively (3 hours), but thereafter WG should be applied in early morning or late Delegate® bees. to during bloom. evening be applied as WG) may of Delegate® formulation Bloom (organic gall midge and/or thrips. bloom for needed just before 1 day bees and beneficial insects. to toxicity Malathion has low 0 days should be of Pristine® applications sequential than two No more 3 days dry it is thoroughly bees until to (3 hours), but is toxic Entrust® 3 days bloom for be applied as needed just before WG may Delegate® 7 days of bloom. Do not apply within 5 days 30 days Postharvest Postharvest interval (PHI) 4 h 4 h 24 h 12 h 12 h 24 h (REI) Restricted entry interval +++ +++ +++ ++++ ++++ (Least + = to + = to (Least Effectiveness Effectiveness most = +++++) 2 pt. 1 pt. acre 6 oz. 2.0 oz. 1.25–2 oz. 18.5–23 oz. +++ Amount of Amount formulation per formulation use WG) 80%) options Malathion Delegate® WG Delegate® Fenbuconazole (Indar® 75 WSP) Pyraclostrobin + Pyraclostrobin (Diazinon AG500) (Malathion 57 EC) boscalid (Pristine® boscalid (Pristine® Spinosad (Entrust® Spinosad (Entrust® Labeled for organic organic Labeled for Gall midge Diazinon Pest/problem Management and twig blight Phomopsis cane Phomopsis No more than two sequential applications of Pristine® should be made before alternating with fungicides that have a different mode of action. Do not make more than four mode of action. than Do not make more a different have that with fungicides alternating should be made before of Pristine® applications sequential than two No more NOTE: blueberry. to applications for Mixwith only water Pristine® year. per crop per acre of Pristine® applications – Flower thrips can be very damaging to flower buds and blooms. Thrips numbers typically increase dramatically as corollas open and bloom progresses. Determining open and bloom progresses. corollas as Thrips dramatically numbers typically increase buds and blooms. thrips can be very flower to damaging thrips – Flower Flower use of insecticides bee and careless and subsequent kill can easily impair crop, are a pollination-sensitive thrips Blueberries is difficult. for when or if blueberries should be treated Only selected and ruin fruit set. pollination insecticides the insecticide should be used during bloom. If (Delegate®) is used, evening should be applied early Delegate® morning or late blueberries: (1) Begin southern highbush and rabbiteye for thresholds treatment measure To on the crop. forage to allowed 3 hours of drying bees are and be given time before the Count and tapping lightly. cluster flower sheet under a by placing a white block areas in a 1-acre to five four to open. Sample begins as soon the flower sampling bloom clusters flower, per (rabbiteye) thrips four thrips (southern highbush) or three than more average you If cluster. the flower the number of thrips count dislodged from and number of flowers more Ifhave you and one in the center). block (one on the border a 5-acre monitor sticky be used to white two could traps Alternatively, some type is recommended. of management 5 and from prebloom 5 days until of choice then some type is the material tactic Assail® than 80–100 thripsof management (southern highbush) or 60–70 thrips is needed. (rabbiteye), first bloom. until prebloom days Table 2. Management strategies for pest and disease problems in blueberry plants from prebloom through green tip (leaf buds) and pink bud (flower buds) tip (leaf buds) and pink bud (flower green in blueberry through pest and disease problems prebloom for from plants 2. Management strategies Table

7 Comments alternating with fungicides that have a different mode of action. Do not apply more a different have that with fungicides alternating year. per crop per acre of Pristine® applications than four consecutive applications before switching to a fungicide with a different mode of with a different a fungicide to switching before applications consecutive action. than 21.0 lb./acre/season. Do not apply more can be made 7 days prior to bloom. Assail® may negatively affect pollinating bees; affect pollinating negatively may bloom. Assail® prior to can be made 7 days than four Do not make more evening. should be made late application therefore, per season. applications of product per than 56 oz. made every during bloom. Do not apply more 7–10 days using another before applications sequential than two Make no more per year. acre mode of action. with a different fungicide without applications consecutive than two Do not make more disease. favor conditions mode of action. than 6.0 lb. Do not apply more with a different a fungicide to switching per year. product per acre Delegate® WG is toxic to bees for 3 hours following treatment. Do not apply Delegate® Do not apply Delegate® treatment. 3 hours following bees for to WG is toxic Delegate® WG in Delegate® spray bees, risk to minimize To on the plants. foraging WG if bees are Do not active. bees are active or early after morning bees are before evening the late times in a 30-day than three period. WG more apply Delegate® nontoxic to bees. Entrust should be applied in early morning or late evening during evening should be applied in early Entrust morning or late bees. to nontoxic bloom. (PHI) Interval Postharvest Postharvest 4 h 3 days Insecticide typically during very applications bloom are pollinators. to damaging 4 h 3 days dry it is thoroughly bees until to it is relatively (3 hours), but thereafter is toxic Entrust 72 h 0 days year. per crop per acre than 70 lb. Do not apply more 48 h ~ 30 days after full bloom. than 3 weeks Do not apply later 72 h 0 days year. per crop per acre than 35 qt. Do not apply more (REI) entry interval Restricted ++ ++ ++ +++++) to most = to (Least = + (Least Effectiveness Effectiveness 5 lb. 3 lb. 2 qt. 6 oz. +++ 1.5 lb. +++++ 12 h 0 days should be made every when 10% bloom. Applications at application 7 days Begin per acre 11–14 oz. +++++ 12 h 0 days Make duringshould be the first application earlyapplications bloom. Subsequent 3.5–4.7 lb. +++++ 72 h 0 days than two Do not make more plus Elevate®. of Captan is a combination Captevate® 18.5-23 oz. +++++ 24 h 0 days should be made before of Pristine® applications sequential than two No more Amount of Amount formulation formulation 4L®) WDG) WDG) 76DF) 50WP) options (Switch® (Switch® 62.5WG) Captan + Captan + boscalid fludioxonil fludioxonil Assail® 70WAssail® 2.4 oz. ++++ 12 h 7 days Application spray. prebloom during Do bloom. It not apply Assail® is an excellent (Elevate® 50 (Elevate® fenhexamid fenhexamid Cyprodinil + Cyprodinil Fenhexamid Fenhexamid Ziram (Ziram (Ziram Ziram (Pristine® WG) (Pristine® Delegate® WG Delegate® Management Management Pyraclostrobin Pyraclostrobin (Entrust® 80%)(Entrust® 1.25–2 oz. +++ (Captevate® 68 (Captevate® Captan (Captec (Captec Captan Captan (Captan (Captan Captan Spraying with insecticides may kill or repel wild bees and honey bees that are needed for adequate pollination and fruit set. and fruit pollination adequate Do needed for not use insecticides with insecticides are kill bees wild beesthat and honey or repel may during bloom. Spraying Pest/ problem Flower thrips Flower Table 3. Management strategies for pest and disease problems in blueberry pest and disease problems 80% –90% bloom 10%–20% bloom until for from plants 3. Management strategies Table

8 Comments alternating with fungicides that have a different mode of action. Do not apply more a different have that with fungicides alternating year. per crop per acre of Pristine® applications than four than two sequential applications before switching to a fungicide with another mode of a fungicide to switching before applications sequential than two per season. per acre than 1.44 qt. Do not apply more Captan). action (e.g., sequential than two Make no more per year. of product per acre than 56 oz. apply more mode of action. with a different using another fungicide before applications (PHI) Interval Postharvest Postharvest 48 h ~ 30 days after full bloom. than 3 weeks Do not apply later (REI) entry interval Restricted ++ +++++ 4h 0 days 14-day 7- to Do can be made at intervals. not apply more applications Subsequent +++++) to most = to (Least = + (Least Effectiveness Effectiveness oz. 5 lb. +++ 72 h 0 days year. per crop per acre than 70 lb. Do not apply more 3 lb. 2 qt. +++ 72 h 0 days year. per crop than 35 qt. Do not apply more per acre 11–14 oz. +++++ 12 h 0 days 10-day Do 7- to not can be made at intervals warrant. Applications when conditions 6.2–15.4 fl. 6.2–15.4 fl. 18.5–23 oz. +++++ 24 h 0 days should be made before of Pristine® applications sequential than two No more Amount of Amount formulation formulation 4L®) 76DF) 50 WP) options (Switch® (Switch® 62.5WG) + boscalid (Abound®) fludioxonil fludioxonil Cyprodinil + Cyprodinil Ziram (Ziram (Ziram Ziram Azoxystrobin Azoxystrobin (Pristine® WG) (Pristine® Management Management Pyraclostrobin Pyraclostrobin Captan (Captec (Captec Captan Captan (Captan (Captan Captan rots Ripe Pest/ and/or problem Alternaria Alternaria (anthracnose) (anthracnose) : No more than two sequential applications of Pristine® should be made before alternating with fungicides that have a different mode of action. Do not make more than four mode of action. than Do not make more a different have that with fungicides alternating should be made before of Pristine® applications sequential than two : No more NOTE blueberry. to applications for Mixwith only water Pristine® year. per crop per acre of Pristine® applications – Scout fields for cranberry fruitworm to determine if and when spraying is needed. Check for fruitworm twice a week from full bloom until 4 weeks after petal 4 full bloom until week from for fruitworm a twice Check for cranberry is needed. – Scout fields if and when spraying Cranberryto determine fruitworm fruitworm larvae Early pale green and damage. berries look for open to Break fruit. mature ripening in more and premature with frass holes in berries, pin-sized tiny, for Examine fruit clusters fall. this pest. control to berry as the first or second should be caught for sprays first. Infestations ripens in a cluster normally infested are ‘Climax’, such as varieties,

9 Comments made before alternating with fungicides that have a different a different have that with fungicides alternating made before of applications mode of action. than four Do not apply more year. per crop per acre Pristine® not apply more than two sequential applications before switching switching before applications sequential than two not apply more Do not Captan). with another mode of action a fungicide to (e.g., per season. per acre than 1.44 qt. apply more conditions warrant. Do not apply more than 56 oz. of product per than 56 oz. Do not apply more warrant. conditions applications sequential than two Make no more per year. acre mode of action. with a different using another fungicide before have emerged. Also effective against Septoria and anthracnose leaf against and anthracnose Septoria effective Also emerged. have and fertilizers, and foliar Do not tank mix with copper spots. because or add acidifying agents do not apply in acidic water When and fruit. damage foliage tank- could these practices to the mix on a small area test mixing this product with others, does not occur phytotoxicity that make sure leaf against and anthracnose Septoria effective Also emerged. have and fertilizers, and foliar Do not tank mix with copper spots. because or add acidifying agents do not apply in acidic water tank- When and fruit. damage foliage could these practices to the mix on a small area test mixing this product with others, does not occur. phytotoxicity that make sure Subsequent applications can be made at 14- to 21-day 14- to can be made at intervals. applications Subsequent Do not tank mix per year. per acre applications four Do not exceed and do not apply in acidic fertilizers, and foliar with copper because could or add acidifying agents these practices water this product with tank-mixing When and fruit. damage foliage phytotoxicity that make sure to the mix on a small area test others, does not occur. 0 h should be of Pristine® applications sequential than two No more 0 h and Pythium after leaves Phytophthora for spray as a foliar Apply 0 h and Pythium after leaves Phytophthora for spray as a foliar Apply 0 days 14-day 7- to can be made at intervals. Do applications Subsequent 0 days 10-day 7- to can be made at intervals Applications when 0 days emerged. have after leaves spray as a foliar Aliette® Apply Postharvest Postharvest Interval (PHI) 4 h 4 h 4 h 24 h 12 h 12 h (REI) Restricted entry interval +++ ++++ ++++ +++++ = +++++) Effectiveness Effectiveness (Least = + to most = + to (Least 5 lb. 4 pt. acre 2.5 qt. 11–14 oz. 18.5–23 oz. +++++ Amount of Amount 6.2–15.4 fl. oz. 6.2–15.4 fl. +++++ formulation per formulation options Fosetyl-Al Fosetyl-Al phosphite phosphite Potassium Potassium (Prophyt®) + boscalid (Abound®) fludioxonil fludioxonil Mono- and Cyprodinil + Cyprodinil (Pristine® WG (Pristine® Azoxystrobin Azoxystrobin Pyraclostrobin Pyraclostrobin (Aliette® WDG) (Aliette® acid (Agri-Fos®) of phosphorous of phosphorous dipotassium salts (Switch® 62.5WG) (Switch® Ripe Ripe and/or and/or root rot root (anthracnose) (anthracnose) (anthracnose) (anthracnose) Phytophthora Phytophthora Alternaria rots Alternaria Alternaria rots Alternaria Pest/problem Management – Review field histories and scout fields for fruitworms and plum curculio to determine if and when spraying is needed. In if and when spraying to determine for fruitworms and plum curculio fields – Review and scout cherry field histories and plum curculio Cranberry fruitworm, fruitworm, least at with a history should be sprayed of infestation Fields blueberries. be a pest of southern highbush and rabbiteye to has not been found plum curculio production areas, Florida pin- tiny for Examine fruit clusters after petal fall. 4 weeks full bloom until from fruitworms twice a week after 14-daybloom. Check for twice immediately on a 7-to interval, beginning will be Control first. larvae normally infested Early berries look for varieties are open to Break and damage. fruit. mature ripening in more and premature with frass holes in berries, sized period. early in the infestation best when these insects sprayed are Fungicide loss of yield. and subsequent in poor bud development resulting defoliation, leaf spot can cause premature leaf spot – Septoria and anthracnose Septoria and anthracnose start leaf spots generally Anthracnose postharvest spring. to harvest prior late and can occur Septoria through specific disease. and by the state leaf spots varies across timing for summer. persist through Table 4. Management strategies for pest and disease problems in blueberry after pest and disease problems 1 month bloom petal fall until for from plants 4. Management strategies Table

10 Comments eyes become inflamed. become eyes eyes become inflamed. become eyes of fruitworms. Confirm needs to be ingested to be effective; therefore, timing is therefore, to be effective; to be ingested needs Confirm Confirm® still small. while fruitworms are Confirm® Apply critical. conserves enemies. natural after petal fall. 1 day fruit clusters. has infested fruitworms when one bush in five Spray 3 days control blueberry Imidan®, excellent applied for provides maggot, 3 days spraying Begin control. of residual 7–10 days Imidan® produces 7 days of fruitworms. control only moderate Sevin® gives 14 days use if skin discontinue or Adjourn®; to be allergic Some users may 14 days use if skin discontinue Asana®; or to be allergic Some users may 14 daysfor cranberryvery fruitworms. control gives good Confirm® Postharvest Postharvest Interval (PHI) 4 h 48 h12 h ~30 days after full bloom. than 3 weeks Do not apply later 12 h 24 h 12 h 24 h 12 h (REI) Restricted entry interval ++ +++ +++ +++++ +++++ +++++ = +++++) ++++++++ Effectiveness Effectiveness (for fruitworms) (for (for fruitworms) (for (for fruitworms) (for (for plum curculio) (for (Least = + to most = + to (Least 3 lb. acre 1.3 lb. 1.3 lb. 16 fl. oz. 16 fl. 1.9–2.5 lb. 2.8–3.2 pt. Amount of Amount 4.8–9.6 fl. oz. 4.8–9.6 fl. ++++ 4.8–9.6 fl. oz. 4.8–9.6 fl. ++++ formulation per formulation EC) EC) EC) 76DF) 80WSP) options Phosmet Phosmet Phosmet Phosmet Malathion Ziram (Ziram (Ziram Ziram Esfenvalerate Esfenvalerate Esfenvalerate Esfenvalerate (Confirm® 2F) (Confirm® Tebufenozide Tebufenozide (Malathion 57 (Adjourn® 0.66 (Adjourn® (Imidan® 70W) (Asana® XL 0.66 (Asana® (Imidan® 70WP) Carbaryl (Sevin® Cranberry fruitworm Pest/problem Management No more than two sequential applications of Pristine® should be made before alternating with fungicides that have a different mode of action. Do not make more than four mode of action. than Do not make more a different have that with fungicides alternating should be made before of Pristine® applications sequential than two No more NOTE: blueberry. to applications for Mixwith only water Pristine® year. per crop per acre of Pristine® applications

11 Comments at 7- to 14-day 7- to at intervals. Do not apply applications sequential than two more with a fungicide to switching before Captan). another mode of action (e.g., per than 1.44 qt. Do not apply more per season. acre 10-day intervals when conditions than 56 oz. Do not apply more warrant. Make no per year. of product per acre applications sequential than two more with a using another fungicide before mode of action. different applications of Pristine® should of Pristine® applications with alternating be made before mode a different have that fungicides of action. than four Do not make more per per acre of Pristine® applications year. crop applications per acre per crop year. per crop per acre applications with with a fungicide Alternate another mode of action. (PHI) 0 days can be made applications Subsequent 0 days 7- to can be made at Applications 0 days sequential than two No more 7 days than three Do not make more Postharvest interval Postharvest 4 h 12 h 24 h 12 h interval (REI) Restricted entry ? +++++ +++++ +++++ +++++) Effectiveness Effectiveness (Least = + to most = = + to (Least acre 2.5 oz. 11–14 oz. 18.5–23 oz. Amount of Amount 6.2–15.4 fl. oz. 6.2–15.4 fl. formulation per formulation WG) options 62.5WG) (Quash®) (Abound®) Cyprodinil + Cyprodinil Metconazole Metconazole Azoxystrobin Azoxystrobin Pyraclostrobin + Pyraclostrobin boscalid (Pristine® boscalid (Pristine® fludioxonil (Switch® (Switch® fludioxonil rots Pest/Problem Management Alternaria and ripeAlternaria No more than two sequential applications of Pristine® should be made before alternating with fungicides that have a different mode of action. Do not make more than four mode of action. than Do not make more a different have that with fungicides alternating should be made before of Pristine® applications sequential than two No more NOTE: blueberry. to applications for Mixwith only water Pristine® year. per crop per acre of Pristine® applications Table 5. Management strategies for pest and disease problems in preharvest blueberries pest and disease problems for 5. Management strategies Table

12 Comments of oviposition until the last berries are harvested. harvested. the last berries until are of oviposition control. of residual 5–7 days Malathion provides dry. dry. of oviposition until the last berries are harvested. harvested. the last berries until are of oviposition effectiveness. of residual 5–7 days Sevin® provides BBM. BBM sprays should protect berries from berries should protect from BBM. BBM sprays the start the last berries until are of oviposition residual 10–14 days Imidan®harvested. provides than twice per season. Do not apply more control. 24 h ground. by of 20 gal. volume a minimum spray Use 1 day the start berries should protect from BBM sprays 7 days applications. between 14 days Allow 3 days it is thoroughly bees until to WG is toxic Delegate® 3 days it is thoroughly bees until to WG is toxic Delegate® 7 days the start berries should protect from BBM sprays 3 days managing for Imidan® of choice is the material Postharvest Postharvest interval (PHI) 4 h 4 h 24 h 12 h 12 h 12 h 24 h interval (REI) Restricted entry +++ +++ +++ +++ ++++ ++++ ++++ + to most = +++++) + to Effectiveness (Least = (Least Effectiveness acre 6 oz. 1.3 lb. 1.5 pt. 3–6 oz. 1.9–2.5 lb. Amount of Amount 1 pt./100 gal. 1 pt./100 formulation per formulation 80S) 70W) AG500) options Malathion Delegate® WG Delegate® Delegate® WG Delegate® Mustang Max™ 4 oz. Carbaryl (Sevin® (Malathion 57 EC) Diazinon (Diazinon drosophila Spotted wing Spotted Pest/problem Management Blueberry maggot (Imidan® Phosmet Blueberry maggot is only a problem for growers north of the Lake City and Live Oak areas. Growers in Gainesville and south of Gainesville should not Growers northBlueberry Oak areas. of the Lake City maggot fly (BBM) – Blueberry and Live growers for maggot is only a problem with blueberry problems The any Blueberryexperience maggot. maggot is a late-seasonharvesting. with BBM, a whitish maggot will appear in the fruit at If pest. infested berries are indicate catches Trap at least one per cultivar. within the bush canopy, sticky with ammonium acetate) yellow (baited traps by hanging the eggs can be monitored lays adult fly that pictures identification for agent county See your stage. the greenish-pink to full green turn when berriesfrom to should be hung in the planting begin Traps present. when adults are it is very important every BBM begins, spray for 7–14 days to spraying Once trapped. as soon adults are has a history spray Ifplanting your of BBM infestation, and further reference. Kingdom or the United must comply shipping blueberries Canada to who are in Florida growers All below. intervals listed are Materials and spray all the fruit has been harvested. until of the the presence cooking for and postharvest samples of harvested for test fruit to inspection including a protocol spraying, of berries, scouting, guidelines for with appropriate Canada. blueberries that must be certifiedto enter states maggot free protocol Canadian The maggot in berries. in and Hardee, Putnam, Levy, Alachua, Columbia, namely Suwannee, counties, in six Florida caught were Flies Florida. new pest for is a relatively (SPD) wing drosophila Spotted eggs in ripening and larvae blueberries, lay inside the berry, part Adults develop in any be a problem of the state. then and could since in other counties been caught have They 2011. with apple cider vinegar. plastic cups and baited can be made from Traps in blueberry placing traps by making can be monitored bushes. the fruits soft Adults and unmarketable. (See Wing Spotted wing drosophila. of spotted control for of the blueberry been registered within the canopy should be placed recently bush. A number of insecticides have Traps Pre- and harvesting essential. proper and handling are control; adequate alone do not provide – Fungicides rots .) Fruit Berry at http://edis.ifas.ufl.edu/in839 Drosophila in Florida Culture hand-harvested highbush and southern For postharvest rapid by cooling. harvest complete of all ripe fruit on the bush, followed timely, by reduced postharvest can be greatly rots is critical and is best cooling harvest Postharvest should be clean-harvested cultivars highbush cultivars, all ripe Rabbiteye every berries on the bush every or less. 10–14 days. 7 days fruit. stacks of palletized air through pull cold use fans to that systems the use of partial-vacuum through or forced-air accomplished Table 6. Management strategies for pest and disease problems in harvest pest and disease problems blueberries for 6. Management strategies Table

13 Comments observed in the spring, the mites are too deep for effective treatment. effective deep for too are observed the mites in the spring, caterpillars. It scale and but if used often it encourages is verycaterpillars. effective, buildup. mite affect certain varieties. Bud mites may be spread via propagation. A via propagation. be spread certainaffect may Bud mites varieties. is the general another in August, by postharvest followed application, proper ensure to with an entomologist Consult recommendation. 3 Thionex® of than 4 qt. Do not apply more timing of these applications. postharvest use only). (for per year EC per acre mature. it should be applied insecticide. However, microbial is an effective DiPel® early stage caterpillars. small, to 1 day as they control to difficult more become caterpillars Foliage-feeding 0 days are the time symptoms seen, and by be readily Blueberry can’t bud mite 0 days 0 days 14 days large for treatment should be used as a salvage Esfenvalerate 14 days earlycaterpillars. very stage to small, is if applied Confirm® effective Postharvest Postharvest interval (PHI) 4 h 4 h 4 h 4 h 24 h only Postharvest 12 h 12 h 24 h only Postharvest very Blueberry specific and only are site infestations bud mite (REI) Restricted entry interval ++ ++ +++ (Least = + to = + to (Least Effectiveness Effectiveness most = +++++) acre 1.5 pt. volume) volume) 4–8 fl. oz. 4–8 fl. ++++ 4.8–16 oz. ++++ 0.5–1.0 lb. 2 gal. (low (low 2 gal. Amount of Amount 2qt./300 gal.2qt./300 ++++ 2 qt./300 gal.2 qt./300 ++++ (dilute spray) (dilute 2 gal./100 gal. gal. 2 gal./100 application or application 3–6 qt./100 gal.3–6 qt./100 ++ formulation per formulation EC) Bacillus options Malathion (DiPel® DF) (DiPel® Endosulfan Endosulfan Esfenvalerate Esfenvalerate (Confirm® 2F) (Confirm® Tebufenozide Tebufenozide (Malathion 57 Pest Spray Oil) Spray Pest (Stoller Golden (Stoller (Thionex® 3 EC) Horticultural oil Horticultural oil (JMS Stylet-Oil®) (Asana® 0.66 EC) (Asana® [BT]thuringiensis (Endosulfan 3EC) mite Azalea caterpillar caterpillars Yellownecked Yellownecked Blueberry bud Pest/problem Management – This is an occasional pest of blueberries in Florida. Use high-volume (300 gal. per acre), high-pressure (200 psi) applications of a postharvest (200 psi) applications insecticide/miticide high-pressure per acre), (300 gal. high-volume Use pest of blueberries is an occasional in Florida. This Blueberry – bud mites old blueberry or destroying with blueberrycanes can help and horticultural and removing In postharvest make two blocks infested oils. of endosulfan. Pruning applications bud mite, by bud mite reduces after harvest this practice also greatly immediately manage bush height; practice or hedging used to is a common Summer topping populations. bud mite reduce of postharvest in the form In sanitation early ripening best visible with a dissecting cultivars, microscope. Blueberry mite, fruiting twigs. eriophyid infested is a tiny bud mite old, removing one- be and cutting back into of endosulfan may application(s) hedging Postharvest and two-year-old should be the primary mite-infested blocks. wood for response management practice. this critical cultural augment helpful to should eliminate treatment broadcast harvest fall as a after into Ant baits employed Imported or fields. – Importedvery ants fire can be ants vineyards, fire important pests in orchards, to the postharvest in addition application high, use a dormant or early application spring broadcast are populations When ant areas. mounds within treated ant fire but seldom all, most, they will carryto baits so that attracted Worker must be ants to the baits back active mounds. control to weeks to 8 up require They acting. slow baits are Ant control. ant fire get better to land for use on all crop is labeled Bait (0.5% methoprene) Ant Fire die-off.Professional Extinguish® colony which causes a gradual with reproduction, Most baits interfere ant their colonies. wet. work best when soil is moist but not baits Ant pyriproxyfen). actingBait (0.5% Ant than Esteem® slower it is somewhat regulator, it is an insect but since growth It is effective, sites. or very Individual hot. rainy, overcast, be cold, expected to are baits when conditions applying ant Avoid should be warm and sunny. temperatures Ideally, is essential. foraging ant Active using insecticide baits should be applied in a Mound treatments survives that treatments. broadcast colony for the occasional when used as needed most effective are mound treatments of mounds. Do bait directly not disturb on top mounds or place the mound. from 3–4 feet circle body with dark wings and are a pale yellow chilli thrips have Adult and fruit scarring. leaf curl stunting, causing bronzing, and fruit, leaves and larvae on young thrips - Adults Chilli feed insert blueberry larvae their eggs into less than 1/16 of an inch in length. Females and newly hatched larval two on blueberry tissues, pass through feed stages that Chilli tissues and fruit. of the blueberry within the canopy sticky placed cards or yellow bush. with white thrips can be monitored Table 7. Management strategies for pest and disease problems in postharvest pest and disease problems management plant for 7. Management strategies Table

14 Comments become inflamed. become is at when the soil temperature days on sunny Apply again in the fall. Allow acting slow but effective. Baits are least 60°F and the soil is moist. for work. to Do not make other imported4 weeks treatments ant fire within 7 rains occur flooding if heavy, reapply need to May 7–10 days. days. Extinguish plus Caution: baits with methoprene land. use on crop Application land. use on crop not labeled for are hydramethylnon is expected within 6 hours of or when rain during of the day the heat of this product. the effectiveness In areas will reduce application be necessary may applications 10–12 weeks repeat heavy infestation, after the initial application. around each mound. Apply gently to avoid disturbing ants. avoid to gently Apply each mound. around trickle, or microsprinkler. It is important the soil (1/2–1 inch moisten trickle, to or microsprinkler. or shortly application prior to of water) after application. for areas bees in the surrounding to Itapplied in early morning. is toxic the first 3 hours after application. spray is dry (approximately 3 hours). is dryspray (approximately the disruption of beneficial insects. application. 24h ground. by of 20 gal. volume a minimum spray Use 24 h if needed, Bait should be applied during the spring Ant and, Esteem® 1 day reduce to Malathionevening should be applied early morning or late 7 days caterpillars. to medium-sized against small Sevin® is also effective 0 days is legal for Bait (0.5% methoprene) Ant Fire Extinguish® Professional 7 days caterpillars. to medium-sized against small Diazinon is also effective 7 days per season. applications than four Do not make more 7 days and 6 inches mixture over of diluted apply 1 gal. Slowly Mound drench. 7 days drip, low-pressure through zone root into Soil Chemigation application. 3 daysWG should be Delegate® be applied as needed. WG may Delegate® 7 days bees until to Toxic per season. applications than four Do not make more 3 days the first 3 hours after for areas bees in the surrounding to It is toxic 14 days use if skin discontinue or eyes Adjourn®; to be allergic Some users may Postharvest Postharvest interval (PHI) 4 h 4 h 4 h 12h 12h 12 h 24 h 12 h 24 h 12 h 12 h 12 h 12 h (REI) Restricted entry interval +++ +++ +++ +++ +++ +++ +++ ++++ ++++ (Least = + to = + to (Least Effectiveness Effectiveness most = +++++) 2 pt. acre 6 oz. 1–2 lb. mound) mound) 1–1.5 lb. 1–1.5 lb. 1.25–2 oz. +++ 1.5–2.0 lb. 1.5–2.0 lb. (2–4 tbsp./ Amount of Amount 4.8–9.6 fl. oz. 4.8–9.6 fl. ++++ 1 pt./100 gal.1 pt./100 ++++ 1 pt./100 gal.1 pt./100 ++++ (3–5 tbsp./ 1000 (3–5 tbsp./ formulation per formulation sq. ft.) sq. (3–5 tbsp./ EC) EC) 80S) Bait) AG500) AG500) options Diazinon Diazinon (Diazinon (Diazinon Malathion (labeled for (labeled for Admire® ProAdmire® oz. 10 fl. (Extinguish® organic use) organic Methoprene Methoprene Pyriproxyfen Pyriproxyfen Assail® 70WPAssail® 2.4 oz. Assail® 70WPAssail® 2.4 oz. Entrust® 80% Entrust® (Esteem® Ant Ant (Esteem® Esfenvalerate Esfenvalerate (Malathion 57 Ant Bait 0.5%) Ant Delegate® WG Delegate® (Adjourn® 0.66 (Adjourn® Mustang Max™ 4 oz. Professional Fire Fire Professional ants beetle) Chilli thrips Flea beetlesFlea Carbaryl (Sevin® White grubs White and Oriental Imported fire European and European garden beetle, beetle, garden Pest/problem Management masked chafer, masked chafer, (Grubs of Asiatic Asiatic of (Grubs

15 Comments immediately after harvest. Two or three fungicide applications after applications fungicide or three Two after harvest.immediately of Septoria major outbreaks prevent to harvest sufficient generally are harvest, following is conducted immediately hedging When leaf spot. per 1.44 qt. Do an application. not exceed consider this is a good time to applications sequential than two per season, and do not apply more acre with another mode of action. a fungicide to switching before of Abound® Do not tank mix with leaf spots. against Septoria and anthracnose or add and do not apply in acidic water fertilizers, and foliar copper or damage fruit because could acidifying agents these practices the mix on a test this product with others, tank-mixing When foliage. does not occur. phytotoxicity that make sure to small area and Septoria leaf spot. Subsequent applications can be made at 14- to 14- to can be made at applications and Septoria Subsequent leaf spot. harvest following applications fungicide or three Two 21-day intervals. of leaf spot. Septoria major outbreaks prevent to sufficient generally are harvest, following is conducted immediately hedging that Assuming four Do an application. not exceed consider this is a good time to per year. per acre applications and do not apply fertilizers, and foliar Do not tank mix with copper because or add acidifying agents these practices in acidic water this product with tank-mixing When or foliage. damage fruit could does phytotoxicity that make sure to the mix on a small area test others, not occur. Do not tank mix with leaf spots. against Septoria and anthracnose or add and do not apply in acidic water fertilizers, and foliar copper or damage fruit because could acidifying agents these practices the mix on a test this product with others, tank-mixing When foliage. does not occur. phytotoxicity that make sure to small area warrant. Do not apply more than 56 oz. of product per acre per year. per year. of product per acre than 56 oz. Do not apply more warrant. using another before applications sequential than two Make no more mode of action. with a different fungicide 0 h and Pythium. effective Also Phytophthora for spray as a foliar Apply 0 h and Pythium. effective Also Phytophthora for spray as a foliar Apply 12 h rots and Pythium root Phytophthora for spray as a foliar Aliette® Apply 0 days 14-day can be made at applications intervals. Apply Subsequent 0 days 10-day 7- to can be made at intervals Applications when conditions Postharvest Postharvest interval (PHI) 4 h 4 h 4 h 12 h 12 h (REI) Restricted entry interval ++++ ++++ ++++ (Least = + to = + to (Least Effectiveness Effectiveness most = +++++) 5 lb. 4 pt. 2.5 qt. per acre 11–14 oz. +++ Amount of Amount formulation formulation 6.2–15.4 fl. oz. 6.2–15.4 fl. ++++ salts of options (Switch® (Switch® 62.5WG) Fosetyl-Al Fosetyl-Al phosphite phosphite Potassium Potassium (Prophyt®) (Abound®) fludioxonil fludioxonil Mono- and Cyprodinil + Cyprodinil dipotassium Azoxystrobin Azoxystrobin phosphorous phosphorous (Aliette® WDG) (Aliette® acid (Agri-Fos®) root rot root spot only anthracnose anthracnose anthracnose anthracnose Septoria leaf Septoria and Septoria and Phytophthora Phytophthora leaf spots and leaf spots only Pest/problem Management During fruit maturation and/or immediately following harvest, fungicide applications may be warranted for control of leaf spot and suppression of dieback diseases and root rots. Start rots. of dieback diseases and root of leaf spot and suppression control for be warranted harvest, may applications fungicide following and/or immediately During fruit maturation first observed. as soon leaf spots are applications after harvest. – Mosthedged immediately cuts can serveDieback southern diseases of southern highbush varieties Hedging highbush varieties are as an entry many for point infection. Blueberry help reduce Rust – rust may with Prophyt® mixed such as Captan of broad-spectrum fungicides application of hedging, the end of each day At pathogens. stem rust can carry on the previous over in winter, not dropped are leaves Where plants. defoliate rust can prematurely varieties, On susceptible production areas. in all Florida is a problem product makes an of both rust and Septoria leaf spots; this chlorothalonil control is labeled for Stik® Weather Bravo in early spring as well. and can cause rust problems foliage year’s can only be used after Stik® harvest will damage fruit. because chlorothalonil Weather Bravo partner However, the strobilurin-containing product rotation Pristine®. for excellent Table 8. Late-season and postharvest blueberry management foliage Table

16 Comments application (see label). Do not apply more than 30 fl. oz. per acre per oz. per acre than 30 fl. (see label). Do application not apply more rain. when it dries ahead of a effective season. Orbit® is more mode of action. a different have that with fungicides alternating before per crop per acre of Pristine® applications than four Do not apply more year. combine with other pesticides, surfactants, with other pesticides, combine or fertilizers. WSP Indar® 75 per year. active) per acre WSP (0.38 lb. of Indar® 75 (DMI) class of fungicides. inhibitor demethylation the sterol belongs to recommended. classes is of different with fungicides Alternation 0 days should be made of Pristine® applications sequential than two No more 42 days Septoria Do only as a postharvestand rust. not Apply for fungicide Postharvest Postharvest interval (PHI) 24 h 24 h 30 days or aerial ground be applied by may Orbit®, another DMI fungicide, 12 h 30 days than 8 oz. or apply more applications than four Do not make more (REI) days (w/o) days Restricted entry interval restrictions) 6.5 ++++ 12 h (with (Least = + to = + to (Least Effectiveness Effectiveness most = +++++) 2.0 oz. +++++ 3–4 pt. 6.0 fl. oz. 6.0 fl. +++++ per acre 18.5–23 oz. +++++ Amount of Amount formulation formulation Stik®) options + boscalid (Orbit® 3.6 E) (Orbit® (Pristine® WG) (Pristine® Propiconazole Propiconazole Chlorothalonil Chlorothalonil Pyraclostrobin Pyraclostrobin (Bravo Weather Weather (Bravo Fenbuconazole Fenbuconazole (Indar® 75 WSP) only Septoria and rust leaf spots Pest/problem Management Septoria, anthracnose, and rust leaf spots four mode of action. than Do not make more a different have that with fungicides alternating should be made before of Pristine® applications sequential than two No more NOTE: blueberry. to applications for Mixwith only water Pristine® year. per crop per acre of Pristine® applications

17 ??? NA NA NA +++ Rust Do not harvest. use before use before ++ ??? ??? NA NA +++ NA Do not harvest. leaf spot use before use before Anthracnose Anthracnose ++ ++ ??? NA NA spot ++++ ++++ NA ++++ ++++++++ NA ++++ NA ++++ +++ NA ++++ NA +++ ++++ Do not harvest. use before use before Septoria leaf + NA NA NA NA NA NA NA +++ +++ +++ +++++ +++++ +++++ +++++ +++++ +++ ++++ ??? +++++ ++++ ++++ ??? Ripe rot Do not use (anthracnose) before harvest. before + ++ ++ ++ NA NA NA NA NA NA NA +++ +++ +++ blight harvest. Do not use before Do not use before + ++ ++ NA NA NA NA NA NA NA NA +++++ Do not use Alternaria rotAlternaria Phomopsis twig before harvest. before ++ ++ NA NA NA NA NA NA NA mold) Do not use Botrytis (gray before harvest. before + + ++ +++++ ++ +++++ ++ +++++ +++++ ++ NA NA NA NA NA NA ++++ +++++ +++++ berry Do not +++++ NA harvest. Mummy Mummy use before use before NA NA NA NA NA NA NA rot +++ +++ +++ +++ +++ harvest. Do not use before Do not use before WDG) Gold®) Captec) (Indar®)* (K-Phite®) NA = no significant activity, ??? = unknown activity, + = very limited activity, ++ = limited activity, +++ = moderate activity, ++++ = good activity, +++++ = excellent activity excellent +++++ = ++++ = good activity, activity, +++ = moderate activity, very ++ = limited + = ??? = unknown activity, limited activity, activity, NA = no significant (ProPhyt®) (Abound®) Fungicide root Phytophthora (Agri-Fos®) Mono- and Mono- and Cyprodinil + Cyprodinil (Captevate®) Azoxystrobin Azoxystrobin Ziram (Ziram) Ziram to prevent rots prevent to Fenbuconazole Fenbuconazole Captan (Captan, (Captan, Captan Pyraclostrobin + Pyraclostrobin phosphorous acid phosphorous acid phosphorous Fosetyl-Al (Aliette® (Aliette® Fosetyl-Al boscalid (Pristine®) dipotassium salts of dipotassium salts of fludioxonil (Switch®) fludioxonil Mefenoxam (Ridomil Mefenoxam Potassium phosphite phosphite Potassium with captan products Fenhexamid + captan Fenhexamid applications, tank mix applications, Fenhexamid (Elevate®)Fenhexamid NA *During mummy berry*During mummy Chlorothalonil (Bravo®)Chlorothalonil NA No more than two sequential applications of Pristine® should be made before alternating with fungicides that have a different mode of action. Do not make more than four mode of action. than Do not make more a different have that with fungicides alternating should be made before of Pristine® applications sequential than two No more NOTE: blueberry. to applications for Mixwith only water Pristine® year. per crop per acre of Pristine® applications Table 9. Efficacy of selected against blueberry fungicides diseases Table

18 Elevate® (fenhexamid) Elevate® Abound® (azoxystrobin) Abound® Ridomil Gold® (mefanoxam) Trade Name and Chemical Name Trade Indar® (fenbuconazole), Orbit® (propiconazole) Indar® (fenbuconazole), Pristine® (boscalid; one component of a two-part (boscalid; one component Pristine® mixture) Switch® (cyprodinil; one component of a two-part (cyprodinil; one component Switch® mixture) Switch® (fludioxanil; one component of a component two-part one (fludioxanil; Switch® mixture) Carboximide Phenylamides Phenylpyrroles Fungicide Class Fungicide Hydroxyanelides Anilopyrimidines Strobilurins or QoI (quinone outside inhibitors) Strobilurins Demethylation inhibitors (DMIs) or sterol inhibitors (DMIs) or sterol inhibitors Demethylation No more than two sequential applications of Pristine® should be made before alternating with fungicides that have a different mode of action. Do not make more than four mode of action. than Do not make more a different have that with fungicides alternating should be made before of Pristine® applications sequential than two No more NOTE: blueberry. to applications for Mixwith only water Pristine® year. per crop per acre of Pristine® applications Table 10. Fungicide Classes With Moderate to High Risk of Resistance Development (Generally Single Sites of Action) Single Sites High to (Generally Risk Moderate Development of Resistance With Classes 10. Fungicide Table

19 Ziram (ziram) Ziram Bravo® (Chlorothalonil) Bravo® Captan (Captan or Captec) (Captan Captan Coppers (numerous formulations) (numerous Coppers Trade Name and Chemical Name Trade (Mono- and dipotassium salts of phosphorous acid), ProPhyt® (Potassium phosphite) (Potassium (Mono- acid), ProPhyt® and dipotassium salts of phosphorous Aliette® (Fosetyl-Al), Agri-Fos® (Mono- and dipotassium salts of phosphorous acid), K-Phite® (Mono- acid), K-Phite® and dipotassium salts of phosphorous Agri-Fos® (Fosetyl-Al), Aliette® Coppers Phthalimides Phosphonates Phthalonitriles Fungicide Class Fungicide Dithiocarbamates Table 11. Fungicide classes with low risk of resistance development (generally multiple sites of action) multiple sites (generally development risk of resistance classes with low 11. Fungicide Table

20 anthracnose anthracnose g Postharvest foliage management foliage Postharvest Septoria leaf spot and rust Orbit®, Agri-Fos®, (Abound®, Prophyt®, Pristine®, Bravo®, Aliette®, or Indar®) Switch®, (Agri Fos®, Aliette®, Pristine®, or Pristine®, Aliette®, Fos®, (Agri Prophyt®) e f Preharvest Alternaria and ripeAlternaria (Abound®, rots or Pristine®, Septoria Switch®) leaf spot (Abound®, or Pristine®, Aliette®, Switch®) fall after petal 20–24 days 20–24 days Alternaria Alternaria and ripe rots (Abound®, or Pristine®, Switch®) after petal fall Alternaria Alternaria and ripe rots (Abound®, or Pristine®, Switch®)

d Petal fallPetal 10–14 days Alternaria Alternaria and ripe rots (Abound®, Pristine®, or Pristine®, Switch®) b + Captan, or + Captan, c applications) Twig blight (Pristine®, (Pristine®, blight Twig Indar® Orbit®) Botrytis (Captevate, or Pristine®, Elevate®, Switch® or a Indar®) Twig blight blight Twig (Pristine® Developmental stageDevelopmental tip Green Bloom (2–3 Bloom times vary because of varietal differences and the environment. Bloom sprays should provide protection against the primary bloom pathogens for the entire bloom period. The bloom period. against the primary protection for the entire should provide bloom pathogens Bloom sprays and the environment. Bloom times vary because of varietal differences spp. activity spp. such as Phomopsis also have against twig may dieback organisms, control rot for registered of the fungicides Many Rust is problematic on some blueberry varieties, especially in Florida and south Georgia, and it can result in complete, premature defoliation on susceptible varieties. Scout for rust in Scout for varieties. on susceptible defoliation premature in complete, and it can result on some blueberry and south Georgia, Rust is problematic especially in Florida varieties, In wet years, preharvest and postharvest rots may be a potential problem. Under these conditions, one to two applications of a preharvest material may be necessary for rot control. control. be necessary rot may of a preharvest applications two material for one to Under these conditions, problem. preharvest be a potential and postharvest may rots In years, wet No more than two sequential applications of Pristine® should be made before alternating with fungicides that have a different mode of action. Do not make more than four mode of action. than Do not make more a different have that with fungicides alternating should be made before of Pristine® applications sequential than two No more NOTE: When using Indar® during bloom, always tank-mix with Captan. Captan provides additional mummy berry control, and it has some activity berry additional mummy against twig Botrytis, control, provides blight, Captan and fruit rots. with Captan. tank-mix using Indar®When during bloom, always Septoria leaf spot is generally controlled with two to four fungicide applications. This disease is more problematic on highbush blueberry varieties, but some rabbiteye varieties on highbush blueberry problematic but some rabbiteye disease is more varieties, This applications. fungicide four to with two controlled Septoria leaf spot is generally may experience premature defoliation from Septoria as well. For leaf spot, Aliette® and other phosphites (ProPhyt®, Agri-Fos®, etc.) are best used after not as harvest are they are since etc.) Agri-Fos®, (ProPhyt®, and other phosphites Aliette® leaf spot, For Septoria as well. from defoliation premature experience may tool. management and they serve resistance rots, as a efficacious against fruit However, it mainly prevents rots when used with Indar®, and it also provides resistance management. management. resistance when used with Indar®, rots and it also provides it mainly prevents However, a blueberry. to applications for Mixwith only water Pristine® year. per crop per acre of Pristine® applications b c d e f g mid to late July. Two to three applications of fungicides from August to mid-September will generally result in good rust management. Some varieties may require yearly rust control. yearly require Some varieties may in good rust management. result mid-September will generally to August from of fungicides applications three to Two July. late mid to number of applications required for bloom may vary from one to three, depending on the season and variety. vary three, bloom may one to for from required number of applications Disease controlled Disease controlled (Fungicides) Table 12. Seasonal “at a glance” fungicidal spray schedule options for blueberry schedule options for spray fungicidal a glance” “at 12. Seasonal Table

® 4 G can be ® Certain weeds broadleaf Annual broadleaf weeds broadleaf Annual Annual broadleaf and grass weeds and grass broadleaf Annual Weeds controlled Weeds weeds Certain and annual grass broadleaf Broadleaf and grass weeds and grass Broadleaf weeds and annual grass Small-seed broadleaf Annual and some perennial weeds and some perennial Annual Annual broadleaf and grass weeds and grass broadleaf Annual to come in contact with any green tissue, or injury may occur. Chateau or injury tissue, occur. may green in contact with any come to ® XP) 80 WDG XP) 80 ® ) 1.4 CS 1.4–2.8 gal. ® ) 4 L 1.2–1.6 qt. TandV) 75 DF TandV) , Karmex ® ® ® ) 75 DF 1.3–2.6 lb. ® ) 10 G 40 lb. ® ) 2.5 TG ® ) 50 DF ) 51 WDG ) 4 G ® ® ® ) 4 L , Gallery ® ) 2 L ® ® 1.4 CS must be applied to well-established plantings and not until at least 1 year after transplanting. Casoron after transplanting. least 1 year well-establishedat and not until 1.4 CS must be applied to plantings ® (Velpar (Diuron, Karmex(Diuron, 0.66–1.33 lb. (Snapshot 1.5–2.0 lb. (Direx 1.5–2.0 lb. 100–150 lb.(Casoron (Devrinol 3–6 fl. oz. 3–6 fl. 4–8 pt.(Velpar 6–12 oz. (Trade name) formulation (Trade of product / A amount (Casoron 100–200 lb. (Callisto 8 lb.(Devrinol (Gallery (Chateau 1.4 CS REI 24 hours. ® 4 G REI 12 hours and Casoron ® may be applied in sequential applications, but not within 30 days of each other. Consult label for herbicides that can be tank mixed to broaden spectrum of weed control. REI 12 hours. spectrum control. broaden of weed to herbicidescan be tank mixed that label for Consult of each other. but not within 30 days applications, be applied in sequential may 5 , MOA Hexazinone 1–2 applied 4 weeks after transplanting. Higher rates may be required to control perennial weed species. Consult label for herbicides that can be tank mixed to broaden spectrum broaden of weed to herbicidescan be tank mixed that label for Consult species. weed perennial control to be required may Higher rates after transplanting. applied 4 weeks Casoron control. , MOA 7 , MOA Diuron 1.2–1.6 : Apply to nonbearing bushes. Allow 60 days between applications and do not apply more than 4 lb. product within a 12-month period. Consult label for herbicidescan be that label for Consult period. product within a 12-month than 4 lb. and do not apply more applications between 60 days Allow nonbearing bushes. to Remarks : Apply REI 12 hours. spectrum control. broaden of weed to tank mixed 12 + Oryzalin 3 , MOA , MOA Isoxaben 2.0–4.0 + 0.5–1 : Apply to bearing and nonbearing bushes. Apply before prebloom, or illegal residues may occur. Can be applied as a split application of 3 oz. followed by 3 oz. with no less 3 oz. by followed of 3 oz. be applied as a split application Can occur. may or illegal residues prebloom, before Apply bearing and nonbearing to bushes. Remarks : Apply herbicidescan be that label for Consult 1% v/v. at or injury Includeoil concentrate a crop and stems, result. may foliage Limit contact with green applications. between than 14 days to determine first should be made on a small acreage application any thus, testing; has conducted limited of Florida University The spectrum control. broaden of weed to tank mixed REI 12 hours. tolerance. cultivar 15 , MOA Napropamide 4 : Apply to bearing and nonbearing bushes. Direct spray solution to the base of the bush. Do not apply to bushes less than 2 years old unless protected by a nonporous wrap, wrap, a nonporous by old unless protected bushes less than 2 years the base of bush. Do not apply to solution to Direct bearingspray and nonbearing to bushes. Remarks : Apply oz. per application than 6 Do not apply more period. oz. in a 12-month cylinders.and final harvest. than 12 Do bud break not apply between Do not apply more or waxed tubes, grow Chateau than 80%. Do not allow greater content old in soils with sand plus gravel bushes less than 3 years to Common name Common a.i. / A lb. 20 Dichlobenil , MOA 4–61.96–3.9 between 60 days Allow or sprinkler control. A single rainfall nonbearing optimum weed bushes. to Remarks : Apply irrigation of 0.5 in. is necessary for of application within 3 days REI or dew. rainfall from foliage wet have bushes that Do not apply to period. product within a 12-month than 600 lb./A Do not apply more product/A or greater. of 150 lb. applications 12 hours. 27 Mesotrione , MOA 0.09–0.19 : Apply to bearing bushes. Crop must be established for 3 or more years. Apply in the spring before leaves are fully expanded. Direct spray solution to the base of the bush to the base of bush to solution to Direct spray fully expanded. are leaves in the spring Apply before years. 3 or more must be established for Crop bearing bushes. to Remarks : Apply for quantity based on soil Do not consult label type. in sandy soil; rates Use lower than 85% sand. greater to soils with Do not apply and fruits. flowers, contact with leaves, minimize of harvest. REI 48 hours. apply within 90 days 12 , MOA Isoxaben 0.5–1.0 and fruit. contact with foliage minimize the base of bush to solution to Direct spray of planting. Do bearing not apply within 1 year and nonbearing to bushes. Remarks : Apply REI 24 hours. a depth of 2 in. within 24 hours application. to or irrigated surface. should be cultivated Napropamide a weed-free should be made to Applications Apply to bearing and nonbearing bushes. Casoron bearing and nonbearing to bushes. Remarks: Apply Apply to bearing and nonbearing bushes, established at least 1 year from transplanting. Direct spray solution to the base of the bush to minimize contact with leaves, flowers, flowers, contact with leaves, minimize the base of bush to solution to Direct spray transplanting. from least 1 year established at bearing and nonbearing to bushes, Remarks: Apply restrictions REI on soil type. Read labels for in the fall. a.i./A) (1.2–1.6 lb. and another application a.i./A) in the spring be applied as a single application (1.2–1.6 lb. may Diuron and fruits. 12 hours. 14 , MOA Flumioxazin 0.188–0.38 Table 13. Preemergence chemical weed control for blueberry for control chemical weed 13. Preemergence Table

22 Annual broadleaf and grass weeds and grass broadleaf Annual Certain annual and perennial broadleaf and Certain broadleaf annual and perennial weeds grass Small-seed broadleaf and annual grass weeds and annual grass Small-seed broadleaf Annual broadleaf and grass weeds and grass broadleaf Annual Weeds controlled Weeds Certain broadleaf and annual grass weeds Certain and annual grass broadleaf Simazine) 4 L 2–4 qt. ® ) 4 AS ® ) 80 WDG Simazine) 90 WDG ® ® ) 80 WP ® ) 50 W ® (Sinbar (Princep 2–4 lb. 2.5–5.0 lb. (Oryzalin, Surflan 0.5–2 lb. (Trade name) formulation (Trade of product / A amount (Solicam (Kerb 2–4 qt. (Surflan®)2–4 qt. 85WDG2.4 – 4.7 lb. 2.2–4.4 lb.(Princep : Do not apply more than 1 lb. a.i./A on plantings less than 6 months old. Apply half the maximum in the spring before bud break and half in the fall. REI 48 hours. and half in the fall. bud break half the maximum in spring Apply before old. less than 6 months a.i./A on plantings than 1 lb. Remarks : Do not apply more 5 , MOA Terbacil 0.4–1.6 : Apply to bearing and nonbearing bushes. Apply in the fall or early winter when temperature is less than 55°F for maximum efficacy. Do not apply to newly planted bushes; to newly planted Do not apply maximum efficacy. is less than 55°F for when temperature in the fall or early Apply winter bearing and nonbearing to bushes. Remarks : Apply than one application product/A or more than 4 lb. Do not apply more control. additional weed or irrigation for with rainfall application Immediately follow establishment. root for wait in 1 year. 5 Simazine , MOA 2–4 : Apply to bearing and nonbearing bushes. Consult label for amount of formulation based on soil texture. Do not apply within 6 months of planting. Rainfall or irrigation is Doof planting. not apply within 6 months based on soil texture. of formulation amount label for Consult bearing and nonbearing to bushes. Remarks : Apply of harvest. Do REI 12 hours. not apply within 60 days spectrum control. broaden of weed to herbicidescan be tank mixed that label for Consult of application. within 4 weeks required Oryzalin 3 , MOA 2–4 : Apply to bearing and nonbearing bushes. Only apply to bushes that have been planted for 1 year or longer. Do not use in soils with less than 3% organic matter. Use in the Use matter. Do not use in soils with less than 3% organic or longer. 1 year for been planted have bushes that Only apply to bearing and nonbearing to bushes. Remarks : Apply REI 12 hours. or shortly emerge spring weeds or after after. harvest before Common name Common a.i. / A lb. 12 Norflurazon , MOA 2–4 : Apply to bearing and nonbearing bushes. Irrigation or rain event of 0.5–1 in. is required within 1 week of application. Consult label for herbicides that can be tank mixed to to herbicidescan be tank mixed that label for Consult of application. within 1 week of 0.5–1 in. is required Irrigation bearing and nonbearing to event bushes. Remarks : Apply or rain REI 24 hours. spectrum control. broaden of weed 3 , MOA Pronamide 1–2

23 Annual and perennial grass weeds grass and perennial Annual weeds and grass Broadleaf weeds and grass Broadleaf weeds broadleaf Annual Broadleaf weeds Broadleaf Broadleaf and grass weeds and grass Broadleaf Annual and perennial grass weeds grass and perennial Annual Annual broadleaf and grass weeds and grass broadleaf Annual weeds and grass Broadleaf Weeds controlled Weeds XP) 80 WDG XP) 80 ® ) 2 SL ® ) 3 SL 1.3–2.7 pt. ® , or Karmex ® ) 4 L 1.2–1.6 qt. ) 1.9 EW1–2 fl. oz. ) 1.9 EW1–2 fl. ® ® ) 2 EC ® DX) 2 EC DX) ® ) 4 L ® 280) 2.34 SL ) 2 EC ® ® 1.5–2 lb.(Direx 1–2 fl. oz.(Aim 1–2 fl. 16–24 fl. oz. 16–24 fl. (Rely oz. 48–82 fl. (Various formulations) (Callisto oz. 3–6 fl. Inteon (Gramoxone (Select Max 2–4 pt.(Firestorm (Diuron, Karmex(Diuron, 9–16 fl. oz.(Arrow®, oz. Select®)fl. 2EC 9-16 oz.(Arrow®, 9–16 fl. (Diquat) 2 L (Diquat) 1.5–2.0 pt. (Fusilade (Trade name) formulation (Trade of product / A amount (Aim : Apply to nonbearing bushes. Include nonionic surfactant at 0.25%–0.5% v/v or crop oil concentrate at 1% v/v. REI 12 hours. Include1% v/v. at nonbearing nonionic surfactant bushes. to Remarks : Apply oil concentrate 0.25%–0.5% v/v or crop at 10 , MOA Glufosinate 1.0–1.5 Direct spray stress. drought are under weeds cool or when are temperatures Efficacy when reduced is goosegrass. Does bearing not control and nonbearing to bushes. Remarks : Apply or tubes, grow wraps, by nonporous unless protected or noncallused stems green to Do not apply and fruit tissue. flower, contact with leaf, minimize the base of bush to solution to Do not apply within 14 spectrum control. broaden of weed to herbicidescan be tank mixed that preemergence label for a.i./A. Consult than 3 lb. Do not apply more containers. waxed of harvest. REI 12 hours. days 9 , MOA Glyphosate 0.5–1.5 preemergence of harvest. label for Do Consult not apply within 14 days and fruits. leaves, stems, contact with green minimize the base of bush to solution to Remarks : Direct spray REI 4 hours. spectrum control. broaden of weed to herbicides can be tank mixed that 27 Mesotrione , MOA 0.09–0.19 to determine first should be made on a small acreage application any thus, testing; has conducted limited of Florida University The bearing and nonbearing to bushes. Remarks : Apply applications. between with no less than 14 days 3 oz. by followed of 3 oz. be applied as a split application Can occur. may or illegal residues prebloom, before Apply tolerance. cultivar spectrum broaden to herbicidescan be tank mixed that label for or injury Consult and stems, result. may foliage contact with green Limit spray 1% v/v. at Include oil concentrate a crop REI 12 hours. herbicides. with burndown be tank mixed Can control. of weed 22 , MOA Paraquat 0.56–1 Direct spray solution to the base of the bush to minimize contact with green stems, leaves, flowers, and fruits. Consult label for herbicides that can be tank mixed to broaden to broaden for herbicidescan be tank mixed that Consult label and fruits. flowers, leaves, stems, contact with green minimize the base of bush to solution to Remarks: Direct spray see Include oil concentrate; a nonionic surfactant, or crop solution per acre. seed oil, of spray use a minimum of 20 gal. methylated is essential; Coverage spectrum control. of weed season. REI 12 hours. a.i./A per crop than 0.096 lb. and more stage, a.i./A during the growing 0.064 lb. a.i./A during the dormant stage, than 0.031 lb. Do not apply more rate. label for 1 Clethodim , MOA 0.07–0.13 : Direct spray to the base of the stem. Use a coarse spray and hooded sprayer to minimize contact with foliage. New canes or shoots can be injured. Include a nonionic New canes or shoots can be injured. contact with foliage. minimize to and hooded sprayer spray a coarse Use the base of stem. to Remarks : Direct spray REI 12 hours. 1% v/v. at surfactant oil concentrate 0.125%–0.25% v/v or crop at SelctMax® is registered in bearing and nonbearing bushes. Arrow®, Select®, and other clethodim formulations registered in nonbearing only. Consult the label for appropriate appropriate the label for Consult in nonbearing only. Select®, registered Arrow®, in bearingand other clethodim formulations and nonbearingRemarks: SelctMax® bushes. is registered of harvest. Do REI 24 hours. not apply within 14 days nonionic surfactant oil concentrate. or crop 7 , MOA Diuron 1.2–1.6 Apply to bearing and nonbearing bushes established at least 1 year from transplanting. Direct spray solution to the base of the bush to minimize contact with leaves, flowers, flowers, contact with leaves, minimize the base of bush to solution to Direct spray transplanting. from bearing and nonbearingleast 1 year to bushes established at Remarks: Apply restrictions Include on soil type. Read labels for in the fall. (1.2–.6 qt./A) and another application in the spring be applied as a single application (1.2–1.6 qt./A) may Diuron and fruits. REI 12 hours. control. weed postemergence improve 1.0% v/v to surfactant at oil concentration 0.25% v/v or crop at 22 , MOA Diquat 0.7–0.9 Include REI 24 hours. a nonionic surfactant and foliage. stems contact 0.06%–0.5% v/v. with green at minimize the base of bush to to Direct spray Remarks : Nonbearing bushes. 1 , MOA Fluazifop 0.25–0.375 Common name Common a.i. / A lb. 14 , MOA Carfentrazone 0.016–0.031 Table 14. Postemergence chemical weed control in blueberry control chemical weed 14. Postemergence Table

24 Annual and perennial grass weeds grass and perennial Annual Broadleaf and grass weeds and grass Broadleaf Weeds controlled Weeds ) ® ) 1.5 EC ® 1.5–2.5 pt. (Poast (Trade name) formulation (Trade of product / A amount (Scythe : Apply to bearing and nonbearing bushes. Consult label for exact rate to control specific grass species. Include a crop oil concentrate at 1 qt./A. Multiple applications may be may at 1 qt./A. Multiple applications concentrate oil Include a crop species. grass specific control to exact rate label for Consult bearing and nonbearing to bushes. Remarks : Apply of harvest. Do REI 12 hours. not apply within 30 days such as bermudagrass. grasses, perennial necessary control to : Bearing and nonbearing bushes. Contact herbicide that should be applied with a shielded sprayer and direct spray to the base of the bush to minimize contact with foliage contact with foliage minimize the base of bush to to and direct spray herbicideshould be applied with a shielded sprayer Remarks : Bearing Contact that and nonbearing bushes. REI 12 hours. spectrum control. broaden herbicide of weed to with preemergence Should be tank mixed the soil. from emerges or crop new growth bark. before and green Apply 1 , MOA Sethoxydim 0.3–0.5 Common name Common a.i. / A lb. Acid Pelargonic 3%–10% v/v

Virginia creeper Virginia Smilax

Perennial

Dandelion

Spotted spurge Spotted

Smartweed

Prickly sida Prickly

Ragweed

Radish, wild Radish,

Pigweed Nightshades

Preemergence Postemergence

annual

Annual

Morning-glory, Morning-glory,

Lambsquarter

Henbit

groundsel

Common Common

Carolina

Geranium, Geranium,

Galinsoga Chickeed -----GFGG-FNG-NNN EG-FGFFGPGGEGFGNN E-GFEE-G-EG-G-FNN E--GEEEEE-G---NNN GFGGGGFFGGG-GGGNN G---FGG-EFEFF-NNN GGG-EEEEEGEGGEGNN G--EFE--GGE-G-E--GGGGGGFGGGGGGGGNN GFGGGGPPGGG-GGPNN GN-FFEFPEPPPPFPNN GP--GEGGGF--F-PNN GGFFGEFGGEGFGPPNN NNNNNNNNNNNNNNNNN GFFFFGEGGGGFGGGPP NNNNNNNNNNNNNNNNN Dichlobenil (Casoron®) Diuron Diuron (Karmex®) Flumioxazin Flumioxazin (Chateau®) Hexazinone Hexazinone (Velpar®) Isoxaben Isoxaben (Gallery®) Mesotrione (Callisto®) Napropamide Napropamide (Devrinol®) Norflurazon (Solicam®) Oryzalin (Surflan®) Pronamide Pronamide (Kerb®) Simazine (Princep®) Terbacil Terbacil (Sinbar®) Carfentrazone Carfentrazone (Aim®) Clethodim (Select®) Fluazifop Fluazifop (Fusilade®) Glufosinate Glufosinate (Rely®) Table 15. Weed Response to Herbicides Response used in Small Fruits to Weed 15. Table

Virginia creeper Virginia Smilax

Perennial

Dandelion

Spotted spurge Spotted

Smartweed

Prickly sida Prickly

Ragweed

Radish, wild Radish,

Pigweed Nightshades

Postemergence

annual

Annual

Morningglory, Morningglory,

Lambsquarter

Henbit

groundsel

Common Common

Carolina

Geranium, Geranium,

Galinsoga Chickweed EGGEFEGEEGEGFGFGG GGFFFGGGGFGGGGPPP NNNNNNNNNNNNNNNNN Glyphosate Glyphosate (Roundup) Paraquat Paraquat (Gramoxone®) Sethoxydim Sethoxydim (Poast®) E = Excellent, G = Good, F = Fair, P = Poor, N = No activity P = Poor, F = Fair, G = Good, E = Excellent,

27 F F F P P P N N N N N N N N N N N N N yellow Nutsedge, Nutsedge, Sedge F F F P P P N N N N N N N N N N N N N purple - F F E E E P P P N N N N N N N N N N Bermudagrass Nutsedge, Perennial grass Perennial F E E E E E E P P P G G G G G G G G G annual F E E E E P P P G G G G G G G G G G G - E E E E E P P P Preemergence G G G G G G G G G G Postemergence Annual grass Annual E E E E E E P P P G G G G G G G G G G F F F E E E E E E E P P G G G G G G G Crabgrass Foxtail Goosegrass fall Panicum, Ryegrass, Dichlobenil, (Casoron®) Dichlobenil, (Karmex®)Diuron, (Chateau®) Flumioxazin, (Velpar®)Hexazinone, (Gallery®)Isoxaben, (Callisto®) Mesotrione, Glufosinate, (Rely®) Glufosinate, Clethodim, (Select®) (Fusilade®) Fluazifop, Carfentrazone, (Aim®) Carfentrazone, Napropamide, (Devrinol®) Napropamide, Norflurazon, (Solicam®) Oryzalin, (Surflan®) (Kerb®) Pronamide, (Princep®) Simazine, Sethoxydim, (Poast®) Sethoxydim, N = No activity P = Poor, F = Fair, G = Good, E = Excellent, Glyphosate, (Roundup) Glyphosate, (Gramoxone®) Paraquat, Terbacil, (Sinbar®) Terbacil, Table 16. Efficacy of preemergence and postemergence herbicides for annual and perennial grass and sedge weed control weed grass and sedge for annual and perennial herbicides and postemergence 16. Efficacypreemergence of Table

28 Comments For use on rabbiteye blueberries. Do blueberries. not apply use on rabbiteye For southern highbush varieties in Florida to Makebecause it can cause overfruiting. first least 40%–50% of the when at application open and about 10% of the flower blooms are application second The fallen. petals have a Use later. should be about 10–18 days If the spray of water/acre. minimum of 40 gal. the lower solution is alkaline (pH 8 or greater), Apply during slow agent. pH with a buffering drying conditions. Hydrogen cyanamide is highly toxic to to cyanamideHydrogen is highly toxic with humans and is a restricted-use material veryrestrictions specific on its handling and including use of an enclosed application, all label directions. Follow tractor cab. buds cyanamideHydrogen will damage flower should be Applications if applied incorrectly. flower natural prior to days made 30 or more is based bud break. Application and vegetative thus the bud development, on stage of flower but it is typically will vary, time of application mid- between applied in north Florida central vary Cultivars in and earlyDecember January. as Use and sensitivity injury. to their response with unknown on cultivars a small-scale test cyanamide. Do not apply hydrogen to response or within 30 of oil application within 14 days applications. fungicide of copper days Postharvest Postharvest interval (PHI) interval (REI) Restricted entry 12 hours 40 days 72 hours NA importance Effectiveness or Effectiveness ++++ ++++ Certain cultivars

a acre formulation per formulation 24–32 oz. (4% 24–32 oz. acid) or gibberellic 24–32 g gibberellic acid applied twice. of 48–64 oz./ Total in most cases acre Dormex™, Krop- Max™, or Budpro® plus a nonionic surfactant not to 0.5% (v/v). exceed Typically 1.5% (v/v) Typically Gibberellic acid Gibberellic 4% liquid (ProGibb 4LS, or GibGro® conc.), 4% Gibbex Dormex™, Budpro®, Dormex™, Budpro®, or Krop-Max™ (50% cyanamide) hydrogen Problem options Management of Amount Product label rates vary. Refer to individual labels. individual labels. to Refer vary. label rates Product a drift nontarget to cleaning after Avoid application. thorough and requires equipment to cyanamide Hydrogen is highly corrosive cyanamide - additional information: Hydrogen A response. uniform a consistent, is needed for coverage spray Thorough and livestock. wildlife, pets, to It tissue. plant is also toxic green to cyanamide be toxic Hydrogen may areas. increase and may bud development cyanamide leaf and flower Hydrogen advances southern highbush plantings. mix is usually needed on mature of spray per acre minimum of 50 gal. of of 1.5% (v/v) or greater concentrations cyanamide, especially at be killedhydrogen by 3) may or injured (Figure stage 3 or beyond at buds sprayed Flower freezes. susceptibility to stage 2 beyond chilling and not progressed significant received have that of suitable cultivars dormant plants product to of 1.5% (v/v) formulated product. Applications formulated bud injury Florida.flower Hydrogen cyanamide should only be in resulted in have greater product of 2.5% (v/v) or formulated of Rates usually effective. are bud development of flower or early December cyanamideJanuary late depending on weather is applied in mid to in Florida hydrogen Typically, chilling. some natural received have that dormant plants applied to cyanamide hydrogen not benefit from may leaf well naturally that Cultivars and timing of sprays. on rate information more labels for to Refer of chilling. Individual progression and the natural ‘Jewel’. and ‘Primadonna’, ‘Windsor’, ‘Sharpblue’, include These cyanamide in Florida. sensitivity hydrogen to than average greater shown Certain have cultivars applications. and in some cases more cyanamide erratic, has been more cyanamidelarge-scale prior to hydrogen Response to and should be tested use. varycultivars hydrogen to in their response not fully dormant are be because plants This may mild winters. following to north Florida, especially compared Florida bud injurycentral and south flower central has been observed, in affect sensitivityto injury bud morphology may from Flower application. southernprior locations to the more at accumulated chilling was and less natural time of application at cyanamide. hydrogen to sensitive be more may ‘Sharpblue’, such as loose bud scales (puffy appearance), have that cyanamide. Cultivars hydrogen fruit set Poor of rabbiteye blueberries Certain southern highbush and cultivars rabbiteye or slow exhibit leaf delayed as development from they emerge This dormancy. can in delayed result fruit ripening and cause stress that plants to set a heavy crop poor or but have leaf canopy delayed development. Table 17. Plant growth regulator use in Florida blueberry use in Florida production regulator growth 17. Plant Table

29 Additional Comments: Comments: Additional Florida because it can cause for southern highbush in blueberry by poor pollination. recommended fruit set of rabbiteye It is not affected plants increase acid may 1. Gibberellic (rainy conditions weather including adverse a number of reasons, for can occur pollination late-ripening and poor-quality, Poor berries. stress in plant which results fruit set, excessive from (especially and insectto flowers damage or activity, bee populations low cultivars, lack of suitable pollinizer extremes during flowering), or temperature high humidity, weather, industryAdditional is based primarily on early ripening southern highbush cultivars. Florida blueberry acid is not widely used in Florida’s thrips). Gibberellic production because flower use on large to this product Inis limited pollination. Florida, natural than fruit set by and ripen later seed counts, low have be smaller, to tend acid treatments gibberellic fruit set from pollination. natural inadequate from suffer that plantings rabbiteye cultivars two Where both sides of the bush each time. spraying of water, in 40 gal. total) (48–64 oz./acre of 24–32 oz./acre applications using two been obtained by have 2. Good results are directed acid gibberellic of applications the first and second Using CDT, (CDT) been successful. cultivar-directed treatments have together, planted are bloom dates with different cultivar, later-blooming the toward are directed fourth and The third sprays to set. helping early flowers cultivar, reach the adjacent will to bloom. Some spray the first cultivar toward acid applied during the season is normally 48 and 64 between gibberellic of total amount The of the early blooming cultivar. drift the later-opening flowers with some spray reaching per acre. oz. and mixing instructions. rates See label for dependent. acid is concentration Gibberellic per acre. of water using a minimum of 40 gal. 3. Apply other nonionic Although of spray. gal. of only 3.2 oz./100 the rate is used at Silwet® carefully. label rates Follow Kinetic®, or Flood. surfactants4. Suggested L-77, Silwet® include X-77, surfactants burn blueberry caution should be used because they could be suitable, may flowers. or very early morning. evening, under slow-drying late occur night, to such as at thought are conditions, acid sprays gibberellic to responses 5. Better (nearly seedless) than nonpollinated be larger to acid and some seed tends of gibberellic set with a combination Fruit pollination. for substitute acid will not completely 6. Gibberellic acid. is important pollination yield and berrywhen using gibberellic Natural optimize berries. even to size, fruit set with However, yet open) and stage 6 (open). but not stage 5 (fully elongated at developmental acid gibberellic from to fruit set receptive are more (florets) 7. Individual flowers making Apply the first application. by bees before worked to open and be least 40%–50% of the flowers at Allow ripening. and late small, is seedless, acid and no pollination gibberellic later. acid 10–18 days of gibberellic application a second

30 Field Office Technical Guide Section IV

NATURAL RESOURCES CONSERVATION SERVICE CONSERVATION PRACTICE STANDARD

INTEGRATED PEST MANAGEMENT (IPM) (Acre) Code 595

CRITERIA

General Criteria Applicable To All Purposes Compliance with Federal, state, and local laws is required (e.g., Food Quality Protection Act (FQPA) of 1996; Federal Insecticide, Fungicide and Rodenticide Act (FIFRA); Chapter 5E-2 and 5E-9 Florida Administrative Code (F.A.C.); and Florida Statue (F.S.), Chapter 487.

Impact to cultural resources, wetlands and Federal and State protected species shall be Mechanical Weed Cultivation evaluated and avoided or minimized to the DEFINITION extent practicable during planning, design and implementation of this conservation practice in A site-specific combination of pest prevention, accordance with established National and Florida pest avoidance, pest monitoring, and pest NRCS policy, General Manual (GM) Title 420-Part suppression strategies. 401; Title 450-Part 401, Title 190-Parts 410.22 and 410.26), and National Planning Procedures PURPOSE Handbook (NPPH) FL Supplements to Parts 600.1 and 600.6, National Cultural Resources 1. Prevent or mitigate off-site pesticide risks to Procedures Handbook (NCRPH), and the National water quality from leaching, solution runoff, Environmental Compliance Handbook (NECH). and absorbed runoff losses. Integrated Pest Management (IPM) is defined as 2. Prevent or mitigate off-site pesticide risks to an approach to pest control that combines soil, water, air, plants, animals, and humans biological, cultural, and other alternatives to from drift and volatilization losses. chemical control with the judicious use of 3. Prevent or mitigate on-site pesticide risks to pesticides. The objective of IPM is to maintain pollinators and other beneficial species pest levels below economically damaging levels through direct contact. while minimizing harmful effects of pest control on human health and environmental resources. 4. Prevent or mitigate cultural, mechanical, and biological pest suppression risks to soil, IPM strategies (Prevention, Avoidance, water, air, plants, animals, and humans. Monitoring, and Suppression or “PAMS”) shall be employed to prevent or mitigate pest CONDITIONS WHERE PRACTICE APPLIES management risks for identified natural resource concerns. On all landuses where pests will be managed. A comprehensive IPM plan utilizing PAM’s strategies will be developed in accordance with

Conservation practice standards are reviewed periodically and updated if needed. To NRCS, FL, April 2014 obtain the current version of this standard, contact your Natural Resources Conservation Service State Office or visit the Field Office Technical Guide. Code 595-2 Field Office Technical Guide Section IV this standard to document how specific pest mitigation. If they do not, use Agronomy management risks will be prevented or Technical Note 5 – Table I to apply appropriate mitigated. The IPM plan must be crop and/or IPM techniques with this practice. land use specific and adhere to applicable For State and Federally Listed T+E Species: elements and guidelines accepted by the University of Florida, Institute of Food and Windows Pesticide Screening Tool (WIN-PST) Agricultural Sciences (UF-IFAS). IPM information results MUST be less than “Intermediate” when can be found at UF – IFAS IPM web-site the planning area is within USFWS designated http://ipm.ifas.ufl.edu/ Gulf Sturgeon Critical Habitat and the NW and NC Florida Listed Mussel Habitat. Refer to the list of If a comprehensive IPM system is not feasible, Hydrologic Unit Areas (HUA) in the FOTG, Section utilize appropriate IPM techniques to adequately II(D)2(a)11(ii) and apply the corresponding HUA prevent or mitigate pest management risks for Map Layer (“7mussels_a_fl###.lyr” in the identified natural resource concerns. “ENDANGERED_HABITAT” geodata folder) in the Customer Service Toolkit. Additonal Criteria To Prevent or Mitigate Off- site Pesticide Risks to Water Quality from When the practice is implemented in South and Leaching, Solution Runoff, and Adsorbed Runoff Central Florida habitats and WIN-PST result is Losses higher or equal to “Intermediate” use the following minimization measures: For identified water quality concerns related to pesticide leaching, solution runoff, and adsorbed runoff, the current version of the USDA-NRCS • Apply chemicals directly to target WIN-PST program will be used to evaluate pest/invasive species. Spot treatment potential risks to humans and/or fish, as techniques suggested include “hack and appropriate, for each pesticide to be used. squirt”, “basal bark” and direct foliar spray. • The minimum level of mitigation required for Follow label instructions for chemical drying each resource concern is based on the final risk times, do not apply chemical too close to a ratings in the “WIN-PST Soil/Pesticide Interaction rain event. Hazards Ratings” Table below: Additional Criteria to Prevent or Mitigate Off- WIN-PST Identified Minimum Mitigation site Pesticide Risks to Soil, Water, Air, Plants, Hazard Rating Index Score Level Animals, and Humans from Drift and Needed Volatilization Losses For identified natural resource concerns related Low or Very Low None Needed to pesticide drift, use Agronomy Technical Note 5 – Table II and 595 job sheet to determine if Intermediate 20 planned conservation practices provide adequate mitigation. If they do not, use Agronomy High 40 Technical Note 5 – Table I and 595 job sheet to apply appropriate IPM techniques with this Extra High 60 practice. The minimum level of mitigation required for drift is an index score of 20. Use Agronomy Technical Note 5 - Pest For Volatile Organic Compound (VOC) emission Management in the Conservation Planning concerns, apply at least one IPM mitigation Process – Table II to determine if planned technique from the Pesticide Volatilization conservation practices provide adequate section of Agronomy Technical Note 5. One

NRCS, FL, April 2014 Field Office Technical Guide Code 595-3 Section IV

example of a mitigation technique is to use IPM Prevention, Avoidance, Monitoring, and Precision Application and there are several Suppression (PAMS) techniques include: examples in the Pesticide Volatilization section. • Prevention - Activities such as cleaning Additional Criteria To Prevent or Mitigate On- equipment and gear when leaving an infested site Pesticide Risks to Pollinators and Other area, using pest-free seeds and transplants, and irrigation scheduling to limit situations Beneficial Species through Direct Contact that are conducive to disease development. For direct contact pesticide risks to pollinators • and other beneficial species in the application Avoidance - Activities such as maintaining area, apply at least two IPM mitigation healthy and diverse plant communities, using techniques from the Pesticide Direct Contact pest resistant varieties, crop rotation, and section of Agronomy Technical Note 5 and refuge management. Agronomy Tech Note 9 – Mitigating Potential • Monitoring - Activities such as pest scouting, Negative Impacts of Pesticides on Pollinators degree-day modeling, and weather Using Integrated Pest Management and Other forecasting to help target suppression Conservation Practices. strategies and avoid routine preventative treatments. Additional Criteria to Prevent or Mitigate Cultural, Mechanical, and Biological Pest • Suppression – Activities such as judicious use Suppression Risks to Soil, Water, Air, Plants, and of cultural, mechanical, biological and Animals chemical control methods that reduce or eliminate a pest population or its impacts For identified natural resource concerns related while minimizing risks to non-target to cultural, mechanical, and biological pest organisms. suppression, (e.g. air quality concerns with burning for weed control or soil erosion concerns IPM guidelines from the UF-IFAS may be with tillage for weed control), natural resource supplemented with information from concerns shall be addressed to FOTG quality appropriately certified professionals. criteria levels. When providing technical assistance to organic producers, the IPM approach to managing pests CONSIDERATIONS should be consistent with the USDA – Agricultural Marketing Service National Organic Program IPM strategies that keep pest populations below standard which includes: economically damaging levels and minimize pest resistance should be utilized, because they also • A diverse crop rotation that reduces habitat help prevent unnecessary pest management risks for major pests and increases habitat for to natural resources and humans. natural enemies. For noxious weed and invasive species control, • Use of “farmscaping” principles to create the minimum level of pest suppression necessary borders of beneficial species habitat. to meet natural resource objectives should be • Farming techniques to improve soil quality. used, however, for the eradication of invasive species, the acceptable pest threshold may be • Planting of locally adapted, pest resistant zero. See Florida NRCS Conservation Practice crop cultivars. Standards Herbaceous Weed Control, Code 315, Adequate plant nutrients and soil moisture, and Brush Management, Code 314 for further including favorable pH and soil quality, can guidance. reduce plant stress, improve plant vigor and

NRCS, FL, April 2014 Code 595-4 Field Office Technical Guide Section IV increase the plant’s overall ability to tolerate 3. Interpretation of the environmental risk pests. analysis. Note: all pesticide label requirements and federal, state, and local On irrigated land, irrigation water management regulations must be followed for all pesticide should be designed to avoid conditions applications. conductive to disease development and minimize offsite contaminant movement. See Florida NRCS 4. Identification of appropriate mitigation Conservation Practice Standard Irrigation Water techniques. See Agronomy Technical Note 5 Management, Code 449, for further guidance. – Table I and 595 job sheet for pesticide risk mitigation management techniques. Producers should be reminded that they are responsible for following all pesticide label 5. A list of pest prevention and avoidance instructions and complying with all applicable strategies that will be implemented, if Federal, state, and local regulations, including applicable. those that protect Threatened and Endangered 6. A scouting plan and threshold levels for each Species. pest, if applicable. Enhancement Considerations 7. Other monitoring plans, if applicable, such as 1. A more intensive level of IPM focused weather monitoring to indicate when primarily on prevention and avoidance pesticide application for prevention is strategies can further minimize pest warranted. management risks to natural resources and 8. A list of accepted pest thresholds or methods humans. to determine thresholds that warrant 2. Precision pesticide application techniques in treatment, if applicable. an IPM system can further minimize pesticide Note: Items 5, 6, 7, and 8 are required to risks to natural resources and humans. An document a comprehensive IPM system, but they example of such precision application is may not be applicable when only a limited seeing eye technology on applicators in number of mitigation techniques are sufficient to citrus. See Agronomy Technical Note 1 – address identified natural resource concerns. Precision Agriculture: NRCS Support for Emerging Technologies and 595 Supplement Record Keeping. for Precision Agriculture. The following records, where applicable, shall be maintained by the producer: PLANS AND SPECIFICATIONS 1. Monitoring or scouting results including the The IPM plan shall be prepared in accordance date, pest population/degree of infestation, with the criteria of this standard and shall and the crop or plant community condition. describe the requirements for applying the 2. When and where each pest suppression practice to achieve its intended purpose. technique was implemented. The IPM plan shall include at a minimum: 3. When and where special IPM techniques 1. Plan map and soil map of site/affected area, were implemented to mitigate site-specific if applicable (use conservation plan maps if risks (e.g., soil incorporation of a pesticide to available). reduce its surface runoff to a nearby stream). 2. Location of sensitive resources and setbacks, if applicable (use conservation plan maps if available).

NRCS, FL, April 2014 Field Office Technical Guide Code 595-5 Section IV

OPERATION AND MAINTENANCE REFERENCES The IPM plan shall include appropriate operation Univ. Florida, IFAS. Applying Pesticides Correctly and maintenance (O&M) items for the client. (SM - 1) These may include: Univ. Florida, IFAS. Agricultural and Related Pest • The plan shall be reviewed and updated Control Applicator License Classifications under periodically in order to incorporate new IPM the Florida Department of Agriculture and strategies, respond to cropping system and Consumer Services (PI-59) pest complex changes, and avoid the National Information System for the Regional development of pest resistance. IPM Centers – IPM Elements and Guidelines • Maintain mitigation techniques identified in (http://www.ipmcenters.org/ipmelements/index the plan in order to ensure continued .cfm) effectiveness. USDA-AMS National Organic Program, National • Calibrate application equipment according to List of Allowed and Prohibited Substances. Extension and/or manufacturer (http://www.ams.usda.gov/AMSv1.0/ams.fetchT recommendations before each season of use emplateData.do?template=TemplateN&navID=N and with each major chemical change. ationalListLinkNOPNationalOrganicProgramHome &rightNav1=NationalListLinkNOPNationalOrganic • Maintain records of pest management for at ProgramHome&topNav=&leftNav=NationalOrgan least two years. When non-Restricted Use icProgram&page=NOPNationalList&resultType=& Pesticides (RUP) are used pesticide acct=nopgeninfo) application records need to include at a minimum: USDA-NRCS GM-190-404 Pest Management Policy The brand or product name o (http://directives.sc.egov.usda.gov/RollupViewer The EPA registration number o .aspx?hid=17015) o The total amount applied Using Farming Bill Programs for Pollinator o The month, day, and year Conservation. o The location of the application (http://plants.usda.gov/pollinators/Using_Farm_ o The crop, commodity, stored product, or site Bill_Programs_for_Pollinator_Conservation.pdf) o The size of area treated o The name of the applicator

When RUP are used Florida Pesticide Law requires applicators to be certified and more detailed information needs to be kept. See the IFAS publication Pesticide Record Keeping (PI-20) for specific requirements. Information on the RUP needs to be recorded within two working days of the application and maintained for two years from the application date.

NRCS, FL, April 2014 V. C. Irrigation Water Management – Description and BMP Documentation

Irrigation Water Management Description

IFAS: Protecting Blueberries from Freezes in Florida (HS968)

IFAS: Improving the Precision of Blueberry Frost Protection Irrigation (FE979)

IFAS: Water Use in Establishment of Young Blueberry Plants (BUL296)

V.C. IRRIGATION WATER MANAGEMENT PLAN - DESCRIPTION Altos Rock, LLC

Objective: Creation of an irrigation water management plan that’s built into a comprehensive resource management plan with compatible requirements.

The goal of an irrigation event is to deliver the correct quantity of water at the time it is required in the most efficient means possible. Many factors are taken into consideration when determining if an irrigation event is needed: crop requirements, growing medium properties and atmospheric conditions. Excessive water applications can stress the plant, lead to rot root and leach valuable nutrients from the root zone which ultimately reduces the crop quality and yields.

Improved or Best Management Practices (BMPs) The list below includes, but is not limited to, the BMPs to be implemented onsite:

• Initiation of irrigation events and their duration will be determined by the utilization of rain gauges, nearby FAWN weather stations, the agriculturalist’s knowledge of the property/area, the condition of the plant and/or crop and an objective method of soil/substrate moisture measurement. • Supplemental irrigation quantities will be delivered through a highly efficient drip irrigation system. • An overhead solid set sprinkler (wobbler) system will only be utilized for frost freeze protection events. • Irrigation events will not exceed the growing medium’s (pine bark/substrate) water holding capacity. • Frequent, light irrigation events are crucial during the growing season which also reduces the potential for leaching of nutrients. • Midday irrigation events will be avoided to minimize evaporative losses • Non-crop areas will not be irrigated. o Exceptions: Grassed middles may need to be irrigated (infrequently) via overhead sprinkler in order to maintain stability and the ability to prevent erosion. • Irrigation well water quality will be monitored frequently, specifically pH, which can affect the availability of micronutrients to the plant.

HS968

Protecting Blueberries from Freezes in Florida1 J. G. Williamson, P. M. Lyrene, and J. W. Olmstead2

Introduction Once fully dormant, a blueberry plant must be exposed to a period of cool temperatures before it will break dormancy Blueberries bloom in late winter or early spring in Florida, and grow normally the following spring. This is a result of making the flowers and young fruit highly susceptible to its chilling requirement. Each cultivar has its own charac- freeze and frost injury. Killing freezes can occur as late teristic chilling requirement. The amount of chilling that as mid to late March throughout much of Florida, long blueberry plants receive in Florida varies considerably from after the initiation of bloom, especially for early-ripening year to year. Temperatures needed to satisfy the chilling southern highbush blueberry cultivars. This publication requirement are generally considered to be between 32°F describes conditions that often occur in commercial and 45°F. However, estimating accumulated chilling is more blueberry fields during and after bloom when the potential complicated than merely recording the number of hours for freeze damage exists. Practices that growers can use to between 32°F and 45°F. Exposure to 1 hour of temperatures minimize freeze damage are also discussed. either slightly above or below the optimum chilling temperature can result in partial chill accumulation: the Dormancy and Cold Hardiness farther from the optimal temperature, the smaller the Most temperate zone plants, including blueberry, enter a amount of chilling. For example, 1 hour of exposure at 42°F dormant period during late fall and winter characterized might equal 1 chill unit, while 1 hour of exposure at 50ºF by no growth and greatly reduced metabolic activity of would equal some fraction of a chill unit. At temperatures aboveground parts. This dormant condition is a defense below freezing, no chilling accumulation occurs. Loss of mechanism that enables plants to survive cold. The accumulated chilling can occur with exposure to very warm development of dormancy and cold hardiness is a gradual temperatures during dormancy. Temperatures between process. In response to shorter days and lower temperatures 32°F and 45°F appear to be most effective at satisfying during the fall, blueberry plant growth slows, dormancy the blueberry chilling requirement, but temperatures begins to develop, and cold hardiness increases. Even before between 45°F and 55°F contribute something to chilling, cold temperatures occur, blueberries develop a certain and temperatures above 70°F between mid-November and amount of cold hardiness. Exposure to cool temperatures mid-February probably negate some accumulated chilling. greatly accelerates dormancy development and increases cold hardiness. Later in the winter, as temperatures con- Another factor that can affect chill accumulation in tinue to drop, cold hardiness continues to increase. Fully blueberries is the presence of leaves during chilling. dormant blueberry plants are quite cold hardy and seldom Blueberry plants in Florida often retain some of their leaves suffer serious damage from cold weather in Florida. throughout much of the winter, especially in southern

1. This document is HS968, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date May 2004. Revised January 2012. Reviewed June 2015. Visit the EDIS website at http://edis.ifas.ufl.edu.

2. J. G. Williamson, professor, P. M. Lyrene, professor emeritus, and J. W. Olmstead, assistant professor, Horticultural Sciences Department; UF/IFAS Extension, Gainesville, FL 32611.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension. Florida. These plants will not accumulate chilling as quickly Wind can be bad or good during a freeze event. If overhead as defoliated plants. irrigation is being applied, wind is a serious problem because it increases evaporative cooling, removes heat from Once chilling is satisfied, warm temperatures cause the field, and interferes with the even distribution of the vegetative and floral buds to initiate growth. In Florida, water. If water is not being applied, the wind is beneficial. most blueberry cultivars initiate flower bud growth before It prevents formation of a cold pool of air near the ground vegetative bud growth. As flower buds pass through the beneath the inversion and prevents the flowers and berries developmental stages from dormant buds to fully open from becoming colder than the air that surrounds them. flowers, they become more susceptible to cold. Experiments On still nights, flowers and berries lose heat faster than the suggest that swollen rabbiteye flowers (stage 3) (Spiers air and become colder than the air. Open blueberry flowers 1978) can withstand temperatures as low as 25°F, but some have sometimes survived temperatures as low as 26°F when may be killed at 21°F or lower. Buds that have opened to the wind blew steadily through the night with no calm the point where individual flowers are distinguishable can periods, whereas flowers in the same stage of development be killed by temperatures of 25°F, and buds with expanded are often killed at 28°F when there is little or no wind and corollas are often damaged or killed at 28°F. Even a slight the dew point is below 26°F. freeze can cause severe damage to fully opened flower buds. Lethal temperatures for southern highbush flowers at Plant Tissue and Stage of Hardiness various developmental stages have not yet been determined. Young blueberry plants are sometimes damaged in field nurseries during late fall and winter if they have not been Freezes and Freeze Protection properly hardened. New spring vegetative flushes can be Freezes during February, March, and April are a much killed by the same temperatures that kill open flowers greater problem for Florida blueberry growers than was and fruit. Completely dormant branches and flower buds anticipated 20 years ago. The shift away from rabbiteye are very cold hardy in midwinter. However, any January blueberries toward early-ripening southern highbush warmth promotes growth and expansion of the flower buds, cultivars has significantly increased the potential for crop and some loss of hardiness accompanies each subsequent losses from late winter and early spring freezes. Currently, if stage of flower bud development. Styles, ovary tissue, some method of freeze protection is not employed, freezes ovules, corollas, and pedicels have similar freezing points; during flowering and early fruit development remain the however, some marginal freezes may kill the styles but not greatest threat to southern highbush blueberry production the corollas, or the ovules but not the ovaries. The relative in Florida. sensitivity of these organs seems to vary from one freeze to another. A partial crop can sometimes be rescued by Several factors affect the severity of damage to blueberry spraying gibberellic acid (GA) on the ovaries of flowers plants, flowers, and fruit in particular freezes. Some of these whose styles or ovules have been killed by marginal freezes. factors are fairly well understood; others have received little However, GA-rescued fruit develop slower, produce smaller study. berries, and ripen later than fruit with viable ovaries, which makes the rescued crop much less profitable for Florida Temperature, Wind Speed, and Dew Point growers who rely on high prices for early-market fresh fruit. Dew point is the temperature at which water vapor in the If the dew point is high and the temperature is only slightly air condenses and is a good indication of the water vapor below freezing, open blueberry flowers may be heavily content of the air. The dew point is important because water coated with frost with no damage to any flower parts. On vapor slows the rate of temperature drop during a freeze. A the other hand, if the air is dry, flowers may be killed with low dew point is always worse than a high dew point. Dry no frost on the plants, even on still nights. air loses heat faster after sunset. Water vapor in all levels of the atmosphere radiates heat to the earth’s surface and Physical Conditions in the Field partially offsets the heat being lost by radiation from the Pine bark mulch culture can result in lower air tempera- ground. Moist air increases the amount of frost formed tures at flower level by as much as 5°F on calm nights with and increases the amount of latent heat released in the field low dew points because it interferes with the transfer of at night. If the air is very dry and there is not much wind, heat from the soil to the air. Pine bark beds on hillsides with flowers can become several degrees colder than the air, and excellent air drainage would probably be less problematic low humidity increases evaporative cooling when irrigation because cold air in the planting would drain to lower is run. ground. If the dew point is high, the pine bark has less

Protecting Blueberries from Freezes in Florida 2 cooling effect. The effect of thoroughly wetting the pine Passive Freeze Protection bark the afternoon before a freeze has not been studied. There are several strategies that can be used by growers to Dry soil and any weeds, alive or dead, lower the tempera- reduce crop loss from freezes. Some are more practical than ture in the field. Any object in the field on which frost can others. form might be expected to lower the temperature of the blueberry plants by contributing to the dehydration of the air during the night. Cultivar Selection The freeze risk to a blueberry crop can be reduced greatly Dry soil lowers the temperature as compared to wet soil by by planting cultivars that flower late. For example, late-flow- two mechanisms. First, dry soil provides little moisture to ering rabbiteye cultivars, such as ‘Powderblue’, ‘Brightwell’, replenish the water vapor that is lost from the air by frost and ‘Tifblue’, seldom suffer significant crop damage from formation. This allows the temperature and dew point in freezes in Gainesville. However, over a period of many years the field to continue to fall after dew and frost begin to at the same location, early-flowering southern highbush form. Second, dry soil conducts heat poorly from the warm cultivars averaged losses of more than 60% unless they were depths of the soil to the cold surface. Wet soil has been protected with overhead irrigation. Unfortunately, late- reported to have a temperature conductivity approximately flowering cultivars tend to ripen later than those that flower eight times greater than that of dry sand. The lay of the land early, and, at present, cultivars that ripen before prices fall with respect to elevation and air drainage patterns greatly around May 20 usually flower before the last hard freezes in affects field temperatures on calm nights with a low dew North and North Central Florida. point, but it is less important as the wind and/or dew point increases. Site Selection Both advective and radiation freezes have damaged Weather Conditioning before the Freeze blueberry fruit and flowers in Florida. Advective freezes The ability of citrus leaves and stems to harden in response occur when a cold air mass moves in rapidly, usually ac- to several weeks during which night temperatures fall below companied by moderate to high winds. During an advective about 50°F before a freeze is well known. Experienced freeze, temperatures at a particular latitude in Florida tend blueberry growers are convinced that blueberry flowers to be similar from farm to farm. The exception might be and flower buds at all stages of development also have some for areas located immediately downwind from a large lake, ability to increase their cold hardiness in response to cold which could be a few degrees warmer than surrounding days preceding the freeze. This phenomenon merits further areas. During an advective freeze, temperatures are gradu- study. ally warmer the farther southeast you are in peninsular Florida. The farther south and east, the less likely it is that Blueberry Variety temperatures will be low enough to freeze berries while the It has long been known by growers that rabbiteye blueberry wind is blowing. This is important because the combination (Vaccinium virgatum) flowers and developing flower buds of wind and freezing temperatures is the hardest situation are less cold hardy than highbush buds and flowers at the to combat when cold-protecting blueberries. same stages of development. Among southern highbush Radiation freezes occur on clear, cold nights when there is cultivars, which are advanced-generation interspecific little or no wind. Heat is radiated from the earth to the open hybrids between a deciduous, northern blueberry spe- sky. Under these conditions, large temperature differences cies (Vaccinium corymbosum from New Jersey) and an can develop over short distances because of elevation evergreen blueberry species from the Florida peninsula (V. variances. Hilltops may be 5°F–10°F warmer than low darrowi Camp), there appears to be wide variation in flower ground at the same latitude. Hilltops in the northern part bud cold tolerance. Just prior to anthesis, the range of varia- of peninsular Florida may be warmer than cold pockets 200 tion in killing temperatures of flowers of different varieties miles farther south. at similar stages of development in the field appears to be on the order of 2°F or 3°F. Pruning If done at the right time of the year, pruning can delay flowering by a week or more. Growers who often lose their crops in freezes can delay flowering by pruning immediately after harvest and providing conditions that promote

Protecting Blueberries from Freezes in Florida 3 vegetative growth during summer and fall. Flower buds protection. Before installing an irrigation system, seek produced on vigorous shoots that result from pruning after advice from an irrigation specialist. harvest in late May and early June mature later in the fall and flower later the following spring. Freeze Protection Methods Overhead irrigation systems—designed for freeze protection with diesel, rather than electric, pumps—are the most widely used and practical method of reducing blueberry fruit losses to freezes in Florida (Figures 1 and 2). Large volumes of water must be pumped to get good protection. The number of gallons per minute needed to protect one acre depends on the temperature, wind speed, relative humidity, and design of the system. Table 1, adapted from Gerber and Martsolf (1965), attempts to describe the relationships between minimum temperature/wind speed combinations and water application rates needed for protection during a freeze. However, this table does not consider the water vapor content of the air. With unusually dry air, higher water application rates are needed than those indicated in the table. In Alachua County, blueberry crops have occasionally been lost between February 20 and March Figure 2a. 20, even in fields protected with overhead irrigation at a rate of 0.2 inches per hour. Temperatures of 26°F combined with 15 mph winds and low humidity exceed the protection capabilities of such a system, even though the same amount of water would protect flowers down to 18°F with no wind.

Figure 1. A blueberry field protected by overhead irrigation during a freeze. While blueberry canes are relatively pliable, the ice load can break canes and uproot plants. Figures 2a and b. Blueberry flower buds protected by overhead irrigation during a severe freeze. Clear ice, as seen here, is usually an indication of adequate freeze protection. Some growers have designed systems that can be quickly altered to deliver 0.4 inch of water per hour by changing The best use of an irrigation system for freeze protection riser heads. A practical system might be able to deliver 0.25 requires experience and close attention to the weather. inch per hour over 10 acres or 0.4 inch per hour over 6 Blueberry flowers and fruit will not freeze if temperatures acres. In most years, the entire 10 acres could be protected. in a weather bureau shelter located alongside the plants at In years with severe late freezes, 4 acres could be allowed the same height as the flowers stay at 32°F or above. Frost to freeze so that the other 6 acres could be given maximum

Protecting Blueberries from Freezes in Florida 4 on the grass between the rows does not necessarily mean protect fruit at various temperature/wind speed combina- that flowers are damaged since, on humid nights, frost tions. However, the values in Table 1 assume normal rela- can form when temperatures in the weather shelter are as tive humidity. If relative humidity is very low, as sometimes high as 36°F. With a clear sky and no wind, a thermometer happens when a cold dry air mass moves into Florida, the placed open to the sky will read about 2°F colder than the values in Table 1 may underestimate the amount of water same thermometer at the same height in a weather shelter. needed for adequate freeze protection. Paying attention to By placing several thermometers throughout a blueberry the dew point temperatures during various nights of freeze field, one can learn a lot about the temperature distribution protection will help take the mystery out of why crops are patterns in that field during radiation freezes. sometimes saved when it seemed too cold and windy and why crops may be lost when it seemed they should have If or when to turn on the irrigation system during a cold been saved. night can sometimes be a difficult decision to make. The answer depends on such factors as the capabilities of the Overhead Irrigation the Afternoon irrigation system, state of development of the crop, relative humidity, temperature, and wind speed. Some of these or Evening Before a Freeze factors cannot be predicted with certainty. The following Experienced fruit growers have long known that irrigating guidelines should be helpful in most but not necessarily their fields the afternoon before an expected freeze can all situations. First, the system should not be used on sometimes reduce the damage caused by the freeze. There nights where the temperature-wind combination produces are four situations in which this practice is potentially conditions more extreme than the system was designed to useful to blueberry growers. handle. Refer to a reliable forecast and Table 1 to determine whether or not the system should be used. First Situation It is a calm afternoon, and minimum temperatures are Calm Nights forecast to be on the borderline between damaging and If there is no wind predicted and a decision is made to run safe. A wet ground may allow the grower to avoid or delay the system, it is usually turned on when a thermometer having to turn on the system during the night. In such situ- hung under the open sky from a bare branch in the coldest ations, even minimum overhead irrigation during the night part of the field reaches 32°F. However, if the dew point should be effective in preventing damage, but irrigating temperature is below 25°F, the system should be turned on frost nights consumes energy, requires large quantities on at 34°F, which will probably be only about half an hour of water, and creates wet plant and soil conditions that are before the temperature reaches 32°F. The temperature has favorable for certain diseases and can leach nutrients from a great tendency to fall to within 1°F of the dew point on the root zone. Therefore, being able to avoid a run is highly clear, calm nights. If the dew point is 26°F or lower and desirable. frost forms on flowers or berries, they will be killed. If the dew point temperature is 30°F or higher and frost forms Second Situation on flowers or berries, they may not be damaged. During The dew point is low and the wind speed is expected to be the morning following the freeze, if there is no wind and erratic during the night, or temperatures are expected to the sun is shining brightly, the irrigation can be turned off be at or below the damaging point with light winds and when icicles are falling rapidly from the plants and have a rising wind expected later in the night. Even though a been falling for more than half an hour. Never turn off rising wind in the night frequently brings in colder, drier the irrigation before icicles are falling no matter what the air behind a secondary cold front, the effect may be to raise temperature. If the dew point temperature is below 20°F, the temperature of the blueberry flowers, as cold surface air continue running irrigation until the shaded air tempera- is mixed with warmer air above the inversion and the wind ture rises to 40°F. If it is windy and the dew point is 26°F or raises the flower temperature to the temperature of the lower, do not turn off the irrigation until most of the icicles surrounding air. On some occasions, growers may be able have fallen. to protect the crop with overhead irrigation before the wind increases, but they lose the crop because of evaporative Windy Nights cooling after the wind begins. On the other hand, dry plants For windy freezes, the decisions about whether or not might have survived the cold wind without damage but did to run irrigation become complicated. Table 1 provides not survive the lower temperatures that occurred before the guidelines for determining the amount of water required to wind broke the inversion. On some such nights, fields that

Protecting Blueberries from Freezes in Florida 5 have been thoroughly wet late in the afternoon before the Alternative Freeze Protection freeze have escaped damage because a higher temperature was maintained before the wind began, whereas crops were Methods lost in dry fields that were not irrigated at all and in fields in Wind machines and helicopters have been used to some which irrigation was run throughout the night. extent to protect blueberry crops from freezes in Florida. Both are based on the fact that on clear, calm nights, a Third Situation strong temperature inversion develops, in which tempera- The grower lacks sufficient pumping capacity to protect the tures within 6 feet of the ground may become much colder entire acreage against a freeze of the expected severity. A than temperatures 50–100 feet aboveground. By mixing decision is made to change the sprinkler heads to a larger these air layers, wind can raise the temperature near the orifice diameter in half of the field and close off the valve to ground by about 4°F, the exact amount varying with the the other half. It may be possible to reduce damage in the strength of the temperature inversion and the effectiveness half that cannot be irrigated during the night by thoroughly of the air mixing. On nights with wind, wind machines wetting the soil during the afternoon before the freeze. and helicopters cannot warm an orchard because no temperature inversion develops. Many windy freezes occur Fourth Situation in Florida during January and February, usually coinciding with the southern highbush bloom period. This may be the most common situation in which growers could improve their crops by adopting a practice that is sel- A single wind machine normally provides a maximum dom used at present. Frequently during January and early increase in temperature of about 5°F over an area of about February, after blueberry flower buds have begun to swell, 10 acres. The cost of installing and maintaining a wind a freeze occurs in which the dew point is so low, the air so machine is fairly high, but the cost of running one is cold, and the probability of some wind during the night so comparatively low (about 8 gallons of gasoline per hour). high that no experienced grower would choose to run the A single helicopter can provide a similar degree of heating irrigation at night for fear of causing massive damage from over an area of about 40 acres, so long as it is constantly evaporative cooling, frozen emitters, broken branches, and flying. A problem with helicopters, apart from their high uprooted plants. Furthermore, many of the flower buds cost, is how to keep them continuously in the air on freeze may still be quite dormant and will survive if nothing is nights. Scheduling problems, pilot fatigue, mechanical done. Frequently in late January, the flower buds may show breakdowns, and the need to refuel can interrupt service. a wide range of developmental stages. For example, 20% of Wind machines are commonly used in some fruit-produc- the buds might be killed if the temperature falls to 24°F, an ing areas of the world where radiation freezes are common. additional 20% will be killed if it falls to 21°F, an additional They are seldom used on blueberries in Florida because of 20% will be killed at 18°F, and 20% would survive 16°F. A the high likelihood of windy freezes during or after bloom. low-risk strategy for the grower would be to thoroughly While Florida blueberry growers should not rely solely on wet the ground the afternoon before freezing temperatures wind machines for cold protection, they may be an effective begin with the goal of raising minimum temperatures in tool during calm radiation freezes and thereby reduce the field by 2 or 3 degrees and reducing the fraction of the annual water use for cold protection during some years. crop lost. Because fruit prices are often higher in years with light crops, and because blueberry plants can sometimes Some growers have recently established new plantings partially compensate losses in fruit number by increasing under polyethylene-covered high tunnels. The potential fruit size, saving part of the crop could be quite rewarding benefit of tunnels with respect to cold protection is the abil- for the grower. ity to use much less water to achieve the same level of freeze protection. In some situations, water may not be needed for The Florida Automated Weather Network (FAWN) (http:// freeze protection under tunnels when it would be needed fawn.ifas.ufl.edu) maintains a series of weather stations in an open field. In other situations, much lower water throughout Florida and provides a useful resource for blue- application rates may be required than would be needed berry growers. FAWN offers long-range climate forecasts in the field. However, high-tunnel production may affect and historical and current weather conditions, including many aspects of blueberry production, including flowering temperature, dew point, and wind speed, along with various and fruit ripening periods, pollination and fruit set, fruit tools, including a chill accumulation program. quality, and pest and disease management. More experience

Protecting Blueberries from Freezes in Florida 6 is needed with high-tunnel blueberry production in Florida to determine if it is economically feasible. Literature Cited Gerber, J. F., and J. D. Martsolf. 1965. Protecting citrus from cold damage. Cir. 287. Gainesville: University of Florida Institute of Food and Agricultural Sciences.

Spiers, J. M. 1978. “Effect of stage of bud development on cold injury of rabbiteye blueberry.” J. Amer. Soc. Hort. Sci.103: 452–455.

Table 1. Suggested overhead irrigation application rates for cold protection of blueberries under different wind and temperature conditions1 Minimum temperature expected Wind speed in M.P.H. 0–1 2–4 5–8 10–12 Application rate (inches/hour) 27°F 0.10 0.10 0.22 0.22 26°F 0.10 0.10 0.22 0.2 24°F 0.10 0.16 0.3 0.4 22°F 0.12 0.24 0.5 0.6 20°F 0.16 0.3 0.6 0.8 18°F 0.20 0.4 0.7 1.0 15°F 0.26 0.5 0.9 --- 1Dry air accompanied by wind requires higher application rates than indicated for a given temperature/wind speed combination. From Gerber and Martsolf (1965). 2Higher application rates than originally suggested by Gerber and Martsolf (1965) due to possible evaporative cooling during windy conditions.

Protecting Blueberries from Freezes in Florida 7 FE979

Improving the Precision of Blueberry Frost Protection Irrigation1 Tatiana Borisova, Tori Bradley, Mercy Olmstead, and Jeffrey Williamson2

Acknowledgements This project is based on an internship report by Tori Bradley to UF/IFAS. Overall, this research project was made possible through the University of Florida IFAS Research internship program that allowed for six weeks of research and training for Tori Bradley, as well as through funding from the Florida Department of Agriculture and Consumer Services, Specialty Crop Block Grant Program. Special thanks go to the following University of Florida faculty members and graduate students for their support and willingness to share their knowledge and expertise: James Boyer, Les Harrison, Elizabeth Conlan, and Skyler Simnitt. Additionally, thanks to the blueberry growers Figure 1. Blueberries from a Central Florida hobby farm (Source: Sally in Florida who participated in the informal discussions Lanigan, UF/IFAS) about blueberry production in Florida, as well as to Sonia the blueberry blooming stage. In practice, growers often Tighe, Florida Fruit and Vegetable Association director of follow a uniform strategy, initiating the irrigation systems membership, for her insights into the Florida blueberry and at 31°F–35°F, with limited consideration of the blueberry peach industries. blooming stage, to minimize the risk of losing yield and Highlights irrigation system freezing due to cold weather. • This study estimates the potential diesel cost savings and • For six production seasons (2009–2015) with growers water savings associated with precision cold protection in Alachua, Marion, Hillsborough, and Polk Counties, irrigation for blueberry when the irrigation decision the number and duration of cold weather events that accounts for cold hardiness at different blooming stages. required cold protection irrigation were much higher given the uniform strategy, compared with the precision • Precision cold protection irrigation is employed at strategy, which translates into significant difference in critical temperatures (32°F and below), depending on pumping costs and water use.

1. This is EDIS document FE979, a publicatiaon of the Food and Resource Economics Department, UF/IFAS Extension. Published October 2015. Please visit the EDIS website at http://edis.ifas.ufl.edu.

2. Tatiana Borisova, associate professor and extension specialist, Food and Resource Economics Department, UF/IFAS Extension, Gainesville, FL. Tori Bradley, Master’s student, Food and Resource Economics Department, UF/IFAS Extension, Gainesville, FL. Mercy Olmstead, assistant professor and extension specialist, Horticultural Sciences Department, UF/IFAS Extension, Gainesville, FL. Jeffrey Williamson, professor, Horticultural Sciences Department, UF/IFAS Extension, Gainesville, FL

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county’s UF/IFAS Extension office. U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension. • The difference between the uniform and precision Potential Money Savings for irrigation strategies was especially significant in northern counties, but it was noticeable for the southern counties Improved Precision in Cold as well. Protection Irrigation • For six production seasons (2009–2015), the average Even with Florida’s generally warm climate, Florida’s estimated difference in water pumping costs for precision blueberries require frost and freeze protection to ensure and uniform strategies was $515 per pump for growers in that cold temperatures do not damage the buds, flowers, Alachua, and $170 per pump for the growers in Hillsbor- and young fruit, thus reducing marketable yields. The ough and Polk Counties, respectively (or $15.8 and $8.5 traditional practice is to use overhead sprinkler irrigation per acre). to reduce the effect of the cold air temperature on sensitive • There was also a significant difference between the plant organs (Figure 2). More information on frost and volumes of water pumped for cold protection given freeze protection can be found by reading EDIS publication precision and uniform practices. The estimated average HS216 [Protecting Blueberries from Freezes in Florida] water savings are 120 and 65 thousand gallons per acre (Williamson et al. 2004). Researchers differentiate frost and per season for the growers in Northern (Alachua and freeze events (Perry 2001), but in this publication, we refer Marion) and Central Florida (Hillsborough and Polk to both events as “cold weather.” Counties), respectively. If the water is valued at $4 per thousand gallons (average residential water rate for An example of one practice that saves growers money customers using 8 thousand gallons per month), the value on production and reduces per-acre water withdrawals of the water use reduction is $481/acre and $259/acre, is adjusting the cold protection irrigation to match cold respectively. Blueberry Production in Florida Is Growing in Importance Florida’s early-ripening southern highbush blueberry cultivars form the basis for potentially lucrative enterprises for Florida growers, allowing them to take advantage of an early market before other states can compete with higher volumes of berries sold at lower prices. During the months of April and May, Florida is the main supplier of blueberries in the United States (Williamson and Crane 2010; Williamson et al. 2012; Williamson et al. 2014). Because of the market advantage of these early-blooming and early- ripening cultivars grown in Florida, the acreage dedicated Figure 2. Cold protection at a private blueberry farm in Alachua County, Florida (Source: Thomas Wright, UF/IFAS) to blueberry production has increased significantly. From 2007 to 2012, the number of farms with harvested hardiness for different blooming stages. We refer to blueberry crops increased by 87 percent (from 442 to this practice as the “precision cold protection irrigation 825 farms), while the harvested acreage increased by 160 scenario” (or just “precision scenario”). In this study, this percent (from 2,376 to 6,179 acres) (USDA 2012a). By 2012, practice is compared with the “uniform cold protection the production value for Florida blueberries had increased irrigation scenario” (or just “uniform scenario”), when the to $62 million (USDA 2012b). irrigation is applied without considering the cold hardiness Four counties had especially significant harvested blueberry for various blooming stages. The objective of this study is acreage (USDA 2012a): Alachua and Marion (northern to estimate the potential savings in diesel costs and water Florida), and Polk and Hillsborough (southern Florida). withdrawal volumes associated with precision cold protec- These counties provided the focal point for this study. tion as compared with the uniform scenario. Because blueberries grown in central and south Florida usually bloom about a week or 10 days before the berries in north Florida, the distinction between the two regions is economically important.

Improving the Precision of Blueberry Frost Protection Irrigation 2 Critical Air Temperatures during 2013). Also, during cold and calm nights with no clouds, there may be pockets of cold air in lower-lying areas, or Blueberry Blooming cold air may be trapped close to the ground (radiation Existing research shows that the critical temperature freeze), potentially cooling the plants to temperatures below depends on bud and flowering stages (also referred to as the temperatures reported by weather stations. Producers phenological stages of blueberry during bloom; Figure 3). can also turn the irrigation system on at temperatures above The temperature can also depend on the blueberry cultivar. 32°F to prevent the irrigation system from freezing later For example, EDIS publication HS216 [Protecting Blueber- during the cold night. Growers are also aware of different ries from Freezes in Florida] (Williamson et al. 2004) cold tolerances at different blooming and post-blooming summarizes past studies (i.e., Gerber and Martsolf 1965; stages. However, several blooming stages can be observed Spiers 1978) and states that for rabbiteye cultivars, the criti- on blueberry plants at the same time, making the cold cal temperature ranges from 25°F for swollen flower buds protection irrigation decision more complex. Topography to 28°F and even higher for fully opened flowers. Similarly, also affects the temperature in different farm locations, and Michigan State University (MSU 2012) and Longstroth these differences in temperature results in irrigating the (2012) discuss bud swell and tight cluster stages as being whole farm to protect the most susceptible areas. relatively cold-resistant, and petal fall/green fruit stage being the most cold-sensitive, even though these studies do As can be seen from this discussion, the decision to turn not specify the blueberry cultivar or the research methods the cold protection irrigation system on is usually based used to establish the critical temperatures. on past experiences of the producers (it is more art than science). There is also one common theme that arises when speaking with growers about their reasons for turning the irrigation systems on at specific temperatures: the risk of losing yield to a cold weather event. Growers would rather initiate their irrigation at a higher temperature to ensure that they will not wait too long and experience an unexpected temperature drop to dangerous levels.

Figure 3. Stages of blueberry blooming (Source: Elizabeth Conlan, Comparing Uniform and Precison Mercy Olmstead, and Jeffrey Williamson, UF/IFAS) Cold Protection Irrigation Given significant need for information to assist Florida Blueberries in the northern and southern counties of producers with frost protection decisions, UF research- Florida are susceptible to cold weather damage at slightly ers are currently conducting laboratory experiments to different calendar periods due to differences in blooming evaluate the hardiness of southern highbush blueberry times, but generally, the months of January, February, cultivars, which are typically grown in Florida. However, and March are the most important for cold protection. until this research is completed, Williamson et al. (2004), Most of March typically comprises the post-bloom period MSU (2012), and Longstroth (2012) are used as the general when cold protection is needed to protect young fruits. guidance for precision cold protection irrigation scenario. In this study, for the northern counties (Alachua and Marion), January 30th to February 25th are used as the Cold Protection Irrigation blooming stage, and for the southern counties (Polk and Hillsborough), January 10th to February 5th are used as the Practices Used by Growers blooming stage. These periods are divided into five equal Informal discussions with several Florida blueberry grow- intervals to approximately represent the transition between ers and Extension experts revealed that growers typically bud stages (Table 1). initiate their irrigation systems between air temperatures of 31°F–35°F, especially during full-bloom and green-fruit Table 2 summarizes temperatures considered critical for stages. Turning the irrigation system on at temperatures turning on cold protection irrigation. To represent the above freezing can be warranted. For example, there is a uniform cold protection irrigation scenario, we consider brief initial reduction in temperature when the cold protec- periods with the average hourly air temperature of less than tion irrigation system is turned on and the plant becomes 33°F (32°F and below) as critical, for all phenological stages wet (due to evaporative cooling) (Bucklin and Haman of blooming and post-blooming. In turn, while additional

Improving the Precision of Blueberry Frost Protection Irrigation 3 research is needed to provide recommendations given can be used with weather data from blueberry-producing blueberry cultivars and production conditions specific for counties to determine the costs of growers for cold protec- Florida, the Michigan State University publication is used tion irrigation. as a general guidance for the precision cold protection irrigation scenario. Note that the critical temperatures are Altering Cold Protection Irrigation generally lower for the precision scenario (except post- blooming stage), implying that this strategy can lower water to Save Costs and Water Use use and pumping costs in comparison with the uniform Duration of Cold Weather Events scenario. When looking at 2010–2015, the number and the duration of cold weather events that required irrigation were For both precision and uniform scenarios, we assume that significantly higher given the uniform cold protection cold protection is applied only given a wind speed of less irrigation as compared with the precision scenario (Table than 10 to 12 miles per hour (Williamson et al. 2004). 3). In Alachua and Marion Counties, the number of cold Finally, once the irrigation system is turned on, we assume weather protection events reduced from approximately 4 that it stays on until the wet bulb temperature rises to 33°F per season, to 2 to 3 per season. The total duration of cold (Jackson et al. undated; Harrison et al. 1972). weather events was significantly longer for the uniform The air temperatures for each year and each county with scenario as compared with the precision scenario (with the significant blueberry acreage were collected from the average difference of 14.8 hours per season). Florida Automated Weather Network (FAWN) online In Hillsborough and Polk Counties, the number of cold database (FAWN 2015). For each county, weather informa- weather events per season is relatively small, still the tion was downloaded for one weather station, and the precision scenario is estimated to reduce the number from average hourly air temperature records measured at 60 cm 1 to 2 per season, to 0 or 1 event. The duration of cold (or approximately 2 feet) height were used. We also exam- weather protection irrigation shrinks by 8 hours per season ined average hourly wind speed (measured at 10 meters or on average. approximately 33 feet, since this data were readily available from FAWN), and wet-bulb temperature (calculated at 2 meter or 7 feet height). Pumping Costs For Alachua and Marion Counties, average reduction in Fuel Costs and Hourly Water Use cold weather protection irrigation associated with the precision scenario can be translated into $315 reduction in A farm diesel cost of $2.50/gallon was used, based on cost per pump per season (recall that we assumed that each subtracting the 2015 federal and state taxes ($0.580 for pump serves 20 acres, and hence, the reduction is $15.8 Florida) (EIA 2015b) from the 2015 diesel prices for the / acre). For Hillsborough and Polk Counties, the average lower Atlantic states ($3.08) (EIA 2015a). The cost estimate reduction in cold protection irrigation was 8 hours that is was verified through discussions with several growers. associated with $170 reduction in pumping costs per pump (or $8.5/acre). Table 4 summarizes estimated cold protec- The average diesel use per pump was assumed to be 8.5 tion irrigation costs for the precision and uniform scenarios gallons of diesel per hour. It was also assumed that pumps for the four counties examined. Not surprisingly, the cold typically employed by growers have the capacity of pump- protection irrigation costs are the highest for Alachua ing approximately 2.7 thousand gallons of water per minute County, and the lowest for Polk County. (or 163 thousand gallons per hour, with an application rate of 0.3 inches/hour). Based on these assumptions, the cost The diesel costs shown in Table 4 only account for one of running a water pump is $21.25/hour, or $0.13/thousand pump running at 8.5 gallons of diesel per hour. Many farms gallons of water. run more than one pump. On larger farms, there may be 20 or more pumps to consider. For example, consider a It was assumed that each pump serves approximately 20 hypothetical farm in Alachua County that has 200 acres of acres. The size of blueberry farms varied significantly in blueberries served by 10 pumps. If the uniform scenario is Florida; hence, the total costs related to cold protection ir- followed, the average cost would be approximately $6,600 rigation varied from farm to farm. We used the area served (assuming the cold protection irrigation needs to be turned by one pump (20 acres) as the basis for our estimations. on about 4 times per season, for the combined duration Table 2 summarizes the assumptions made in this study and of 41 hours). In contrast, if the precision cold protection

Improving the Precision of Blueberry Frost Protection Irrigation 4 irrigation scenario is followed, the grower would pay almost time interval for blooming and post-blooming stages; 50 percent less, or an average of $3,700 per season (reduc- however, the timing of blooming can shift from year to ing the number of the irrigation events to 2 to 3 times year, depending on weather conditions. Furthermore, we per season, with the total duration of 17 hours). This is a made a set of assumptions to characterize common grower difference of almost $3,000 per season for this large farm. practices and farm setup, while acknowledging some For growers who wish to determine their own pumping variability in real grower decisions. Finally, in estimating costs based on their individual operations, Tables 6 and 6 water pumping costs, we accounted for diesel costs only, illustrate the necessary calculations. and we did not consider other possible costs, such as labor and pump depreciation and maintenance. Cold Protection Irrigation Water Use There is also a substantial difference in the volumes of Conclusions water being pumped for cold protection given precision Growers who follow the research-based critical temperature and uniform scenarios. We assume that cold protection recommendations for cold protection techniques given requires 162.9 thousand gallons per hour to protect 20 acres different flowering stages can decrease their diesel costs for of blueberry, or 8.1 thousand gallons to protect 1 acre for cold protection irrigation. However, accurate temperature 1 hour (Table 5). Reduction in irrigation duration by 14.8 monitoring in blueberry fields is critical and may require hours means 120.2 thousand gallon of water use reduction several onsite strategically placed weather stations or per acre per season for Alachua and Marion Counties. For sheltered thermometers. It is also important to understand Polk and Hillsborough counties, 8 hour reduction in cold the temperature differences between a weather station or weather protection duration results in 64.8 thousand gallon sheltered thermometer and actual plant tissue. Depending reduction in water use per acre per season. Note that in on the county, growers can expect to reduce the length of some seasons, the difference can be even higher. If the water cold protection irrigation by up to 41 hours per season, is valued at $4 per thousand gallons (which is an estimated reducing pumping costs by up to $871 per pump per season average price paid by residential customers using 8 thou- (or $44 per acre per season). Average reductions are $315 sand gallons per month, Raftellis Consultants Inc. 2012), per pump per season in Alachua and Marion Counties (or then the water use reduction resulting from switching from $15.8 / acre per season) and $170 per pump per season in the uniform to precision strategy would be valued at $481/ Polk and Hillsborough Counties (or $8.5/acre). Growers acre for Alachua and Marion Counties, and $259/acre for can also expect significant reductions in water use for cold Hillsborough and Polk Counties. protection: averages per season are 120.2 thousand gallons per acre in Marion and Alachua, and 64.8 thousand gallons Study Limitations per acre for Polk and Hillsborough Counties. This water The temperatures for the precision cold protection irriga- use reduction is valued highly (one of the metrics can be tion scenario used in this study are based on a publication the average price of $4/thousand gallons paid by residential developed by Michigan State University (MSU 2012); customers for tap water, Raftellins Consulting 2012). these temperatures are similar to the recommendations in It should be noted that this study does not consider the Longstroth (2012), and are not developed specifically for yields predicted using alternate cold protection strategies, Florida. Additional research will allow for a more accurate or the possibility of irrigation system freezing if the irriga- definition of the critical temperature for blueberry cultivars tion system is not turned on. Some strategies may prove grown in Florida so that growers can ensure high yields to be more effective than others in terms of amount of while conserving water and saving money on cold protec- berries lost versus the amount of berries the grower is able tion irrigation. to save and harvest following the cold weather events. More Longstroth (2012) acknowledges slight damage in petals research is needed to determine the best strategies for cold or flowers for temperatures close to the recommended protection that results in the highest yield. When coupled temperatures. Not all petal or flower damage translates into with the savings from adhering to the research-based yield losses; and neither Longstroth (2012) nor MSU (2012) critical temperatures, a high yield strategy will become even offers any description of the effect (or the lack of effect) of more lucrative for growers. petal or flower damage on yield.

In our analysis, we made a few assumptions that may oversimplify some cases. Specifically, we considered a fixed

Improving the Precision of Blueberry Frost Protection Irrigation 5 References Full_Report/Volume_1,_Chapter_2_County_Level/Florida/ st12_2_033_033.pdf Bucklin, R.A., and D.Z. Haman. 2013. Reading the simplified psychrometric chart for frost protection. ABE-372. UF/IFAS United States Department of Agriculture (USDA). 2012b. Extension, Gainesville, FL. http://edis.ifas.ufl.edu/ae406 2012 blueberry statistics. United States Department of Agriculture, Washington, DC. Gerber, J.F., and J.D. Martsolf. 1965. Protecting citrus from cold damage. Circular 287. UF/IFAS Extension, Gainesville, United States Energy Information (EIA). 2015b. Federal FL. and state motor fuel taxes. http://www.eia.gov/petroleum/ marketing/monthly/xls/fueltaxes.xls Florida Automated Weather Network (FAWN). 2015. Data access: Report generator. UF/IFAS Extension, Gainesville, United States Energy Information Administration (EIA). FL. http://fawn.ifas.ufl.edu/data/reports/ 2015a. Weekly lower Atlantic No.2 diesel retail prices, 1997–2015. http://www.eia.gov/dnav/pet/hist/LeafHandler. Jackson, J., L. Parsons, and D. Martsolf. Undated. Using wet ashx?n=PET&s=EMD_EPD2D_PTE_R1Z_DPG&f=W bulb temperature to determine when to turn off irrigation systems used for cold protection. UF/IFAS Extension, United States Geological Survey (USGS). 2010. Water use Gainesville, FL. http://fawn.ifas.ufl.edu/tools/irriga- data for Florida. National Weather Information System: tion_cutoff/about.php Web Interface. http://waterdata.usgs.gov/fl/nwis/water_use/

Harrison, D.S., J.F. Gerber, and R.E. Choate. 1972. Sprinkler Williamson, J.G., & J.H. Crane. 2010. “Best management irrigation for cold protection. Circular 348 (Tech.), UF/IFAS practices for temperate and tropical/subtropical fruit Extension, Gainesville, FL. crops in Florida: Current practices and future challenges.” HortTechnology. http://horttech.ashspublications.org/ Longstroth, M. 2012. Using sprinklers to protect blueberries content/20/1/111.full from spring freezes. Michigan State University Extension, East Lansing, MI. http://blueberries.msu.edu/uploads/files/ Williamson, J.G., P.M. Lyrene, and J.W. Olmstead. 2004. Using%20Sprinklers%20to%20Protect%20Blueberries%20 Protecting blueberries from freezes in Florida. HS968. UF/ from%20Spring%20Freezes.pdf IFAS Extension, Gainesville, FL. http://edis.ifas.ufl.edu/ hs216 Michigan State University (MSU). 2012. Michigan blueberry facts: Spring critical temperatures. Michigan State University Williamson, J.G., J.W. Olmstead, and P.M. Lyrene. 2012. Extension, East Lansing, MI. http://blueberries.msu.edu/ Florida’s commercial blueberry industry. HS742. UF/IFAS growing_blueberries/spring_critical_temperatures Extension, Gainesville, FL. http://edis.ifas.ufl.edu/ac031

Perry K.B. 2001. Frost/freeze protection for horticultural Williamson, J.G., J.W. Olmstead, G.K. England, and P.M. crops. Horticulture Information Leaflet 705 3/94. North Lyrene. 2014. Southern highbush blueberry cultivars from Carolina Cooperative Extension, Raleigh, NC. http://con- the University of Florida. HS1245. UF/IFAS Extension, tent.ces.ncsu.edu/frostfreeze-protection-for-horticultural- Gainesville, FL. https://edis.ifas.ufl.edu/hs1245 crops.pdf

Raftellis Consultants, Inc. 2012. 2012 Florida Water Rate Survey. Raftellis Consultants, Inc., 976 Lake Baldwin Lane, Suite 204, Orlando, FL 32814.

Spiers, J. M. 1978. “Effect of stage of bud development on cold injury of rabbiteye blueberry.” Journal of the American Society of Horticulture Science 103: 452–455.

United States Department of Agriculture (USDA). 2012a. 2012 census, Volume 1, Chapter 2: County level. Agricul- tural table 33. Berries: 2012 and 2007. USDA, Washington, DC. http://www.agcensus.usda.gov/Publications/2012/

Improving the Precision of Blueberry Frost Protection Irrigation 6 Table 1. Florida blueberry bud stages and critical temperatures used in the study Bud development, blooming, Dates Critical air temperatures for cold and post-blooming stages protection irrigation Southern counties Northern counties Precision scenario Uniform scenario (Polk & Hillsborough) (Alachua & Marion) 3–Tight Cluster Jan 10–Jan 14 Jan 30–Feb 3 23°F (–5.0°C)* 33°F (0.6°C) 4–Early Pink Jan 15–Jan 19 Feb 4–Feb 8 25°F (–3.9°C)* 33°F (0.6°C) 5–Late Pink Jan 20–Jan 24 Feb 9–Feb 13 27°F (–2.8°C)* 33°F (0.6°C) 6–Full Bloom Jan 25–Jan 29 Feb 14–Feb 18 28°F (–2.2°C)* 33°F (0.6°C) 7–Petal Fall Jan 30–Feb 5 Feb 19–Feb 25 32°F (0.0°C)* 33°F (0.6°C) 8–Post-bloom – young fruit Feb 6–Mar 15 Feb 26–Mar 31 33°F (0.6°C)** 33°F (0.6°C) * Source: MSU (2012). ** assumed to be the same as common growers’ practice.

Table 2. Assumptions made to characterize blueberry farming practices Assumption description Value Area served by one water pump, acres 20.0 Water pump capacity, thousand gallons of water per minute 2.7 Water application rate for cold protection, inches per hour 0.3 Water pump diesel use, gallons of diesel per hour 8.5 Diesel cost, $/gallon $2.50 Diesel cost per hour per pump, $/hour $21.25 Cost of water pumping per acre per hour, $/(hour*acre) $1.06 Cost of water pumping, $/thousand gallons of water $0.13

Improving the Precision of Blueberry Frost Protection Irrigation 7 Table 3. Cold weather events per county per year, 2010–2015 County (City) Year Number of cold events Total duration of cold events (hours) Precision cold Uniform cold Precision cold Uniform cold Difference protection protection protection protection irrigation irrigation irrigation irrigation Northern Florida Alachua County 2010 6 12 40 81 41 (Alachua) 2011 0 5 0 32 32 2012 2 3 22 34 12 2013 7 10 48 69 21 2014 0 1 0 3 3 2015 5 5 36 46 10 Marion County (Citra) 2010 5 7 32 50 18 2011 0 2 0 12 12 2012 2 2 16 22 6 2013 2 5 17 34 17 2014 0 0 0 0 0 2015 2 3 15 21 6 Average for Northern FL 2.4 4.2 17.4 31.1 14.8 Central Florida Hillsborough County 2010 2 5 10 51 41 (Dover) 2011 0 3 0 18 18 2012 1 1 10 10 0 2013 1 1 4 4 0 2014 0 0 0 0 0 2015 1 1 8 8 0 Polk County 2010 1 4 2 37 35 (Lake Alfred) 2011 0 1 0 6 6 2012 1 1 5 5 0 2013 1 1 2 2 0 2014 0 0 0 0 0 2015 0 0 0 0 0 Average for Central FL 0.6 1.4 3.2 10.5 8.0

Improving the Precision of Blueberry Frost Protection Irrigation 8 Table 4. Estimataed cost and savings per pump (serving 20 acres) for cold weather events in four Florida counties, January 2010 – March 2015 Year Alachua County Marion County Precision Uniform Savings Precision Uniform Savings 2010 $850.0 $1,721.3 $871.3 $680.0 $1,062.5 $382.5 2011 $0.0 $680.0 $680.0 $0.0 $255.0 $255.0 2012 $467.5 $722.5 $255.0 $340.0 $467.5 $127.5 2013 $1,020.0 $1,466.3 $446.3 $361.3 $722.5 $361.3 2014 $0.0 $63.8 $63.8 $0.0 $0.0 $0.0 2015 $765.0 $977.5 $212.5 $318.8 $446.3 $127.5 Year Hillsborough County Polk County Precision Uniform Savings Precision Uniform Savings 2010 $212.5 $1,083.8 $871.3 $42.5 $786.3 $743.8 2011 $0.0 $382.5 $382.5 $0.0 $127.5 $127.5 2012 $212.5 $212.5 $0.0 $106.3 $106.3 $0.0 2013 $85.0 $85.0 $0.0 $42.5 $42.5 $0.0 2014 $0.0 $0.0 $0.0 $0.0 $0.0 $0.0 2015 $170.0 $170.0 $0.0 $0.0 $0.0 $0.0

Table 5. Estimation of diesel cost per gallon of water Assumptions Water application rate: 0.3 inches per hour Area irrigated by one pump: 20 acres Farm diesel cost: $21.25 per pump per hour Convert water application rate into gallons per hour 1 acre-inch per hour: 27,154.29 gallons of water Water application rate per hour per acre by one pump (at 0.3 inches/hour): 27,154.29 gallons*.3 inches per hour = 8,143.59 gallons per acre per hour Total water application rate per hour for 20 acres served by one pump 8,143.59*20 acres=162,871.74 gallons water per pump per hour Estimate cost of water pumping $21.25 / 162,871.74 gallons = $0.00013/gallon of water or $0.13/thousand gallons of water

Table 6. Pumping cost estimation Diesel price ($/gallon): $2.50 Assumed gallons of diesel used per pump per hour (gallon/hour) 8.5 Diesel cost for one pump per hour ($/hour) $2.50*8.5= $21.25 of diesel per pump per hour Diesel cost per hour per farm: Diesel cost per hour per pump ($21.25) * number of pumps Diesel cost per hour per acre Diesel cost per hour per pump/acres served by the pump

Improving the Precision of Blueberry Frost Protection Irrigation 9 Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office.

BUL296

Water Use in Establishment of Young Blueberry Plants 1

Dorota Z. Haman, Allen G. Smajstrla, Robert T. Pritchard, Fedro S. Zazueta and Paul M. Lyrene2

BLUEBERRY PRODUCTION IN is the only blueberry available at this time. Before FLORIDA May 20, the average price is very high per pound. After June 1, the average price drops to around one Blueberries show great promise as a Florida fruit dollar per pound. Highbush plants are more difficult crop. Although blueberries are grown in many other to establish and have a shorter life expectancy than states, Florida's climate allows fruit to reach maturity the rabbiteye varieties. They are also much more earlier, avoiding competition with growers in other sensitive to water stress and they require frequent states, thus commanding high prices. This advantage irrigation to grow and produce even when well has been increased by the recent introduction of established. earlier-yielding highbush varieties. Rabbiteye blueberries are native to Florida. Currently, about 2,100 acres of blueberries are These are relatively easy to grow and are considered grown in Florida. This acreage is expected to expand the highest yielding type of blueberry for north as more growers take advantage of Florida's unique Florida. The plants are more vigorous, longer living, market window and new early-yielding blueberry higher yielding, and later ripening than the highbush varieties, and as existing growers expand their variety. However, the rabbiteyes experience some acreage. Presently, the blueberry acreage is evenly problems with fruit setting due to pollination divided between rabbiteye and highbush varieties. problems, thus yields do not always reach the However, for the last 10 years, new plantations have expected levels. If pollination problems can be been almost exclusively planted to highbush varieties. solved, it is very likely that rabbiteyes will again account for a significant percentage of new plantings Newly developed early ripening highbush since they are much easier to grow, and once varieties are of the greatest interest to Florida growers established, live longer and have higher potential at this time. These varieties are lower yielding and yields. During the establishment period the plants much more difficult to grow than rabbiteye varieties, respond very well to irrigation; however, once well but the early ripening fruit brings high prices since it established, they are relatively insensitive to drought.

1. This document is BUL296, one of a series of the Agricultural and Biological Engineering Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date August 1994. Reviewed December 2005. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 2. Dorota Z. Haman, Associate professor; Allen G. Smajstrla, Professor; Robert T. Pritchard, Graduate Research Assistant; Fedro S. Zaueta, professor, Agricultural and Biological Engineering Department; and Paul M. Lyrene, Professor, Horticultural Science Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611.

Water Use in Establishment of Young Blueberry Plants 2

In addition, rabbiteye blueberries can be In Florida, blueberries are usually grown on mechanically harvested which results in a significant sandy soils with low water holding capacities and decrease in production cost. large pore spaces. Thus, water applications must be frequent and relatively small to avoid water losses BLUEBERRY IRRIGATION from the root zone. This requires precise irrigation scheduling. Microirrigation, which was used in the The importance of irrigating young blueberry experiment on establishment of blueberry plants, plants has been recognized for some time. In dry applies water directly to the crop root zone. The years, irrigation is very important during fruit amount and placement of water can be precisely formation. Berry size can be significantly increased controlled with this system to minimize application in a dry year if irrigation is used to maintain moist losses. The microirrigation system was controlled soil conditions in the plant root zone. Sufficient using magnetic switching tensiometers (Smajstrla et moisture is not only critical during fruit production al., 1988). but is also important for the future of the plants since adequate irrigation during bud formation is critical With the microirrigation system used in this for next year's crop (Lyrene and Crocker, 1991). study, water was not applied to the grass alleyways Irrigation is critical to successful production in between plant rows. Also, organic pine bark mulch Florida because rainfall is typically low during the minimized evaporation losses from the soil surface. time of blueberry bud formation. Irrigation requirements would need to be adjusted for other plant sizes, irrigation systems and/or production Blueberries are often grown using organic practices. For example, a greater volume of water mulches such as pine bark. The mulch provides would be required with a sprinkler irrigation system protection against high temperatures, decreases because water would be applied to the entire soil evaporation from the soil, and with time, provides surface rather than being limited to the mulched area organic material to the soil. Organic mulches may near each plant. also help reduce soil pH which is beneficial to the blueberry plant. Earlier research at the University of Figure 1 and Figure 2 present the cumulative Florida demonstrated the importance of an organic irrigation for both varieties of blueberry during three mulch ground cover and precise irrigation scheduling years of the experiment. The significant increase in on the growth of young rabbiteye and highbush the slope of the lines during the last year of the blueberry plants (Haman et al., 1988). experiment for all treatments (with exception of 20-cb highbush) reflects the higher water requirement The recommendations presented in this of the larger plants and the lower rain contribution publication were developed based on a three year during that year. experiment on water requirements for establishment of young blueberry plants which was conducted at the University of Florida. The project was partially funded by the St. Johns River and the Southwest Florida Water Management Districts. Both native rabbiteye and newly developed early-yielding highbush varieties were studied. Two-year old, container-grown plants were transplanted to the field at the beginning of 1991. The experiment ended in December 1993. Total water use (evapotranspiration) of the plants, irrigation requirements, crop yield, and vegetative plant growth were evaluated for the three years after transplanting. Three different threshold levels of soil water tension were evaluated for Figure 1. Cumulative irrigation over three years of the experiment for Rabbiteye blueberries. scheduling irrigations. The threshold soil tension were set at 10 centibars (cb), 15 cb, and 20 cb. Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office.

Water Use in Establishment of Young Blueberry Plants 3

both varieties. In 1993, the rate of growth for the 15-cb and 20-cb treatments was very small and significantly lower than the 10-cb treatment ( Figure 3 ).

Figure 2. Cumulative irrigation over three years of the experiment for Highbush blueberries.

YOUNG BLUEBERRY WATER USE

Water use in gal/acre and inches/acre for the first Figure 3. Blueberry growth during three years of the three years after transplanting for both varieties of experiment. blueberries is presented in Table 1 , Table 2 , Table 3 , Table 4 , Table 5 , Table 6 . The numbers were Rabbiteye plant heights increased mainly in the developed for different plant densities depending on first year after transplanting (1991), especially in the the field spacing between the plants. These quantities 10-cb treatment. During that year, the 10-cb plants are relatively small because they are specific for the reached approximately 5 ft. The 15-cb and 20-cb young, small, microirrigated blueberry plants studied treatments were slightly shorter and reached 5 ft at in this research. The portion of the water demand the end of the second year. By the end of 1993, the which must be supplied by irrigation depends on 10-cb rabbiteye treatment plants were approximately system efficiency and rainfall effectiveness and can 6 ft tall with 15-cb slightly shorter at 5.6 ft and 20 cb be calculated using the water budget method. at 5.3 ft. RESPONSE OF YOUNG BLUEBERRY In 1991, following common practice for young PLANTS TO IRRIGATION plants to stimulate vegetative growth, the flowers were removed from the plants, preventing fruit from Growth of blueberry plants was measured setting. This is reflected in the 1991 plant growth monthly. The volume of each plant canopy was pattern. Most of the plants showed an increase in calculated from three measurements: the height, the volume in all months until September. In 1992 and width along the plant row, and the width 1993, most of the increase in plant size occurred perpendicular to the row. during the three months after fruit harvest. Little change in plant size occurred during the spring Plant volumes increased each year for all months as fruit was set and grew to maturity. treatments. Both plant size and rate of increase were greater for rabbiteye plants as compared to highbush Fruit production data were collected during the plants. Among highbush plants only the 10-cb last two years of the research and are presented in treatment showed significant growth, most of which Table 5 . The two types of rabbiteye plants yielded occurred in the last year of the experiment. During differently and for this reason are presented 1993, the 10-cb plants grew almost 2 ft, while the separately. 15-cb and 20-cb highbush plants showed very little increase in height in all three years due to water stress and poor establishment of the root system. Overall, the 10-cb treatment had the highest growth rate for Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office.

Water Use in Establishment of Young Blueberry Plants 4

The fruit for all three cultivars matured at different times of the year, and yields varied as a function of time of harvest. In both years, yields were lowest for the early-producing Sharpblue (highbush) variety, largest for the late-producing Powderblue (rabbiteye) variety, and intermediate for the midseason rabbiteye variety, Premier. This is important since timing of harvest is critical to blueberry growers. Early-producing varieties are in great demand because early yields command much higher market prices.

Sensitivity to water stress was greatest in the Figure 4. Potential evapotransporation calculated from the highbush variety. Both vegetative growth and yield Penman equation as compared to actual were strongly dependent on irrigation. Only the evapotranspiration of highbush and Rabbiteye blueberries. well-watered (10 cb) treatment was well established native to Florida, and highbush, which is an and healthy at the end of three years. The plants in this introduced variety. Growers are very interested in treatment were much larger and produced highbush plants due to their early ripening and the significantly more berries. All rabbiteye plants were high prices which blueberries bring early in the year. well established by the end of three years and there were only small differences between the water The rabbiteye variety is easier to establish and treatments. easier to grow successfully under Florida conditions. Plants grow rapidly after transplanting, and were Figure 4 shows the annual distributions of monthly ET for the well-watered rabbiteye and relatively insensitive to imposed water stresses up to 20 cb. As compared to highbush plants, rabbiteyes highbush plants as a function of time during the first have a deeper root system which allows them to three years after transplanting. The ET pattern is uptake water from a larger volume of soil, resulting consistent with the patterns of climate demand as in more efficient irrigation scheduling and fewer measured by Penman ETo (reference losses to deep percolation. At the end of the third year evapotranspiration). In 1991 the peak monthly ET of this project, the establishment of rabbiteye occurred in June. For all three years, the peak blueberries was good under all treatments. There was monthly ET for both varieties occurred in July. This only small visible difference among plants. closely follows the peak climate demand, and it is largely a result of levels of solar radiation and As compared to rabbiteye, the highbush variety temperatures. is much more difficult to establish and requires more precise water management. Plants exhibit high Evapotranspirational (ET) rates were larger for sensitivity to water stress and require frequent the rabbiteye plants as compared to the highbush irrigation for good establishment. It takes longer for plants. This difference was due to plant size and highbush plants to develop a root system. Most of the growth characteristics. The rabbiteye plants are more roots in this variety are located relatively close to the vigorous and rapidly-growing than the highbush soil surface, which makes efficient irrigation plants. scheduling more difficult. As a result, more water is CONCLUSIONS AND lost to deep percolation. RECOMMENDATIONS Well-watered highbush plants (10-cb treatment) The establishment and water requirements of were very well established at the end of the experiment. However, two drier treatments showed plants are strongly dependent on the blueberry much less vegetative growth and much lower yields variety. Two typical types of blueberry plants were than the well-watered plants. It can be concluded that evaluated in this experiment: rabbiteye, which is Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office.

Water Use in Establishment of Young Blueberry Plants 5

Table 5.

Table 5. Blueberry yield in lbs/acre* as a function of the three irrigation levels during first two years of fruiting. Year Irrigation Rabbiteye Rabbiteye Highbush Treatment Powderblue Premier 1992 10 cb 7,760 3,680 3,080 15 cb 6,250 3,450 1,060 20 cb 8,310 3,360 520 1993 10 cb 5,590 4,690 2,200 15 cb 5,260 4,430 2,040 20 cb 5,890 3,710 820 * Yield calculated based on plant density of 1000 plants /acre the establishment of highbush blueberries under Florida conditions will not be successful without irrigation, and that irrigations should be scheduled at 10 cb. REFERENCES

Haman D.Z., A.G. Smajstrla and P.M. Lyrene. 1988. Blueberry response to irrigation and ground cover. Proc. Fla. State Hort. Soc. 101:235-238.

Lyrene, P.M. and T.E. Crocker. 1986. Florida blueberry handbook. Circular 564. Univ. of Fla. Coop. Ext. Ser., Gainesville, FL. 15 pg.

Lyrene P.M. and T.E. Crocker. 1991. Commercial blueberry production in Florida. SS-FRC-002. Univ. of Fla. Coop. Ext. Ser., Gainesville, FL. 49

Smajstrla A.G., D.Z. Haman and P.M. Lyrene. 1988. Use of tensiometers for blueberry irrigation scheduling. Proc. Fla. State Hort. Soc. 101:232-235. Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office.

Water Use in Establishment of Young Blueberry Plants 6

Table 1.

Table 1. Water use in inches per acre per month as a function of density for rabbiteye blueberries. Density (plants/acre) 600 700 800 900 1000 1100 1200 Year 1 APR 0.2 0.3 0.3 0.3 0.4 0.4 0.4 MAY 1.0 1.2 1.3 1.5 1.7 1.8 2.0 JUN 1.4 1.6 1.8 2.1 2.3 2.5 2.8 JUL 1.5 1.7 1.9 2.2 2.4 2.7 2.9 AUG 1.4 1.6 1.9 2.1 2.3 2.6 2.8 SEP 1.3 1.5 1.7 1.9 2.2 2.4 2.6 OCT 1.1 1.3 1.5 1.6 1.8 2.0 2.2 NOV 0.7 0.8 0.9 1.1 1.2 1.3 1.4 DEC 0.3 0.4 0.4 0.5 0.5 0.6 0.6 Year 2 JAN 0.3 0.4 0.4 0.5 0.5 0.6 0.6 FEB 0.3 0.4 0.4 0.5 0.6 0.6 0.7 MAR 0.5 0.6 0.7 0.8 0.9 1.0 1.1 APR 1.1 1.3 1.5 1.7 1.9 2.1 2.3 MAY 1.3 1.9 2.1 2.4 2.6 2.9 3.2 JUN 1.6 1.9 2.2 2.4 2.7 3.0 3.2 JUL 2.0 2.2 2.5 2.9 3.2 3.5 3.8 AUG 1.9 1.7 2.0 2.2 2.5 2.7 3.0 SEP 1.2 1.3 1.5 1.7 1.9 2.1 2.3 OCT 0.9 1.1 1.2 1.4 1.5 1.7 1.8 NOV 0.6 0.6 0.7 0.8 0.9 1.0 1.1 DEC 0.3 0.4 0.5 0.5 0.6 0.6 0.7 Year 3 JAN 0.3 0.4 0.5 0.5 0.6 0.6 0.7 FEB 0.3 0.3 0.3 0.4 0.4 0.5 0.5 MAR 0.4 0.4 0.5 0.5 0.6 0.6 0.7 APR 1.2 1.4 1.7 1.9 2.1 2.3 2.5 MAY 2.6 3.0 3.4 3.9 4.3 4.7 5.2 JUN 2.9 3.4 3.9 4.3 4.8 5.3 5.8 JUL 3.2 3.7 4.2 4.7 5.3 5.8 6.3 AUG 3.1 3.6 4.1 4.6 5.1 5.6 6.1 SEP 2.6 3.0 3.5 3.9 4.3 4.8 5.2 OCT 1.2 1.4 1.5 1.7 1.9 2.1 2.3 NOV 0.6 0.7 0.9 1.0 1.1 1.2 1.3 DEC 0.6 0.7 0.8 0.9 1.1 1.2 1.3 Data not available for first 3 months of the first year.

Table 2.

Table 2. Water use in inches per acre per month as a function of density for highbush blueberries. Density (plants/acre) 600 700 800 900 1000 1100 1200 Year 1 APR 0.3 0.4 0.4 0.5 0.5 0.6 0.6 MAY 0.3 0.4 0.4 0.5 0.6 0.6 0.7 JUN 0.7 0.9 1.0 1.1 1.2 1.4 1.5 Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office.

Water Use in Establishment of Young Blueberry Plants 7

Table 2.

JUL 0.7 0.9 1.0 1.1 1.2 1.4 1.5 AUG 0.7 0.8 1.0 1.1 1.2 1.3 1.4 SEP 0.6 0.8 0.9 1.0 1.1 1.2 1.3 OCT 0.5 0.6 0.7 0.8 0.9 0.9 1.0 NOV 0.5 0.5 0.6 0.7 0.8 0.8 0.9 DEC 0.3 0.4 0.4 0.5 0.5 0.6 0.6 Year 2 JAN 0.4 0.4 0.5 0.6 0.6 0.7 0.7 FEB 0.4 0.4 0.5 0.5 0.6 0.7 0.7 MAR 0.4 0.5 0.6 0.6 0.7 0.8 0.8 APR 0.5 0.6 0.7 0.8 0.8 0.9 1.0 MAY 0.7 0.8 0.9 1.0 1.1 1.2 1.4 JUN 0.9 1.0 1.1 1.3 1.4 1.6 1.7 JUL 1.1 1.3 1.5 1.7 1.9 2.1 2.9 AUG 1.1 1.3 1.5 1.7 1.9 2.1 2.2 SEP 1.0 1.1 1.3 1.5 1.6 1.8 1.9 OCT 0.8 1.0 1.1 1.3 1.4 1.5 1.7 NOV 0.5 0.6 0.7 0.8 0.9 1.0 1.0 DEC 0.3 0.4 0.4 0.5 0.5 0.6 0.6 Year 3 JAN 0.2 0.2 0.2 0.2 0.2 0.3 0.3 FEB 0.2 0.2 0.3 0.3 0.3 0.4 0.4 MAR 0.3 0.4 0.4 0.5 0.6 06 0.7 APR 1.0 1.2 1.4 1.6 1.7 1.9 2.1 MAY 1.8 2.1 2.4 2.7 3.0 3.3 3.6 JUN 2.0 2.4 2.7 3.0 3.4 3.7 4.0 JUL 2.3 2.7 3.1 3.4 3.8 4.2 4.6 AUG 2.1 2.5 2.9 3.2 3.6 3.9 4.3 SEP 2.0 2.3 2.6 3.0 3.3 3.6 3.9 OCT 1.2 1.4 1.6 1.8 2.0 2.2 2.4 NOV 1.0 1.2 1.3 1.5 1.7 1.8 2.0 DEC 1.0 1.2 1.4 1.5 1.7 1.9 2.0 Data not available for first 3 months of the first year.

Table 3.

Table 3. Water use in gallons per acre per month as a function of density for rabbiteye blueberries.

Density (plants/acre) 600 700 800 900 1000 1100 1200 Year 1 APR 5922 6908 7895 8882 9869 10856 11843 MAY 27239 31779 36379 40859 45398 49938 54478 JUN 37813 43485 49697 55909 62121 68333 74546 JUL 39312 45865 52417 58969 65521 72073 78625 AUG 37865 44176 50487 56797 63108 69419 75730 SEP 35003 40837 46671 52504 58338 64172 70006 OCT 29641 34581 39521 44461 49401 54341 59281 NOV 18916 22069 25221 28974 31527 34679 37832 DEC 8323 9710 11097 12485 13872 15259 16646 Year 2 JAN 8656 10098 11541 12984 14426 15869 17312 FEB 8948 10439 11931 13422 14913 16405 17896 Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office.

Water Use in Establishment of Young Blueberry Plants 8

Table 3.

MAR 14745 17202 19660 22117 24575 27032 29490 APR 30506 35590 40674 45759 50843 55927 61012 MAY 42961 50121 57281 64441 71601 78762 85922 JUN 43766 51060 58355 65649 72343 80238 87532 JUL 51808 60443 69078 77712 86347 94982 103616 AUG 40051 46726 53401 60076 66751 73426 80101 SEP 31096 36279 41462 46645 51827 57010 62193 OCT 24492 28574 32656 36738 40820 44902 48984 NOV 14875 17354 19833 22312 24791 27271 29750 DEC 9321 10874 12427 13981 15534 17088 18641 Year 3 JAN 9352 10910 12469 14028 15586 17145 18703 FEB 6703 7820 8937 10054 11172 12289 13406 MAR 9510 11095 12680 14265 15850 17435 19020 APR 33537 39781 44717 50306 55896 61485 67075 MAY 70134 81823 93511 105200 116889 128578 140267 JUN 78356 91415 104475 117534 130593 143653 156712 JUL 85603 99870 114137 128404 142671 156938 171205 AUG 82793 96592 110391 124190 137989 151788 165587 SEP 70762 82556 94350 106144 117937 129731 141525 OCT 31450 36691 41933 47175 52416 57658 62899 NOV 17235 20108 22981 25853 28726 31598 34471 DEC 170069 19914 22789 25604 28449 31294 34138 Data not available for first 3 months of the first year.

Table 4.

Table 4. Water use in gallons per acre per month as a function of density for highbush blueberries.

Density (plants/acre) 600 700 800 900 1000 1100 1200 Year 1 APR 8356 9749 11141 12534 13927 15319 16712 MAY 8882 10363 11843 13323 14804 16284 17765 JUN 20035 23374 26713 30052 33391 36730 40069 JUL 20166 23527 26888 30249 33610 36971 40332 AUG 19245 22453 25660 28868 32075 35283 38490 SEP 17436 20342 23248 26153 29059 31965 34871 OCT 13949 16273 18598 20923 23248 25572 27897 NOV 12337 14393 16449 18505 20561 22617 24673 DEC 8422 9825 11229 12633 14036 15440 16843 Year 2 JAN 9915 11567 13219 14872 16524 18177 19829 FEB 9558 11151 12744 14337 15930 17523 19116 MAR 11404 13305 15205 17106 19007 20907 22808 APR 13665 15942 18220 20497 22775 25052 27330 MAY 18378 21441 24504 27566 30629 33692 36755 JUN 23137 26993 30849 34105 38561 42417 46274 JUL 30995 36161 41327 46493 51659 56825 61991 AUG 30421 35491 40561 45631 50701 55772 60842 SEP 26334 30723 35112 39502 43891 48280 52669 OCT 22740 26530 30320 34110 37900 41690 45480 NOV 14171 16532 18894 21256 23618 25979 28341 Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office.

Water Use in Establishment of Young Blueberry Plants 9

Table 4.

DEC 8533 9956 11378 12800 14222 15645 17067 Year 3 JAN 3988 4652 5317 5981 6646 7311 7915 FEB 5134 5990 6846 7701 8557 9413 10268 MAR 8994 10493 11992 13491 14990 16489 17987 APR 27982 32645 37309 41973 46636 51300 55964 MAY 49032 57204 65976 73548 81720 89892 98064 JUN 54793 63925 73057 82189 91321 100453 109585 JUL 62157 18516 82876 93235 103595 113954 124314 AUG 58228 67933 77638 87343 97047 106752 116457 SEP 53355 62247 71140 80032 88925 97817 106710 OCT 32057 37400 42743 48085 53428 58771 64114 NOV 27255 31798 36340 40883 45425 49968 54510 DEC 27722 32343 36963 41584 46204 50824 55445 Data not available for first 3 months of the first year.

Table 6.

Table 6. Water use per plant in gallons during first three years of blueberry establishment. Year 1 Year 2 Year 3 Month HB* RE* HB RE HB RE Jan - - 17 14 7 16 Feb - - 16 15 9 11 Mar - - 19 15 15 16 Apr 14 10 23 51 47 56 May 15 45 31 72 82 117 Jun 33 62 39 72 91 131 Jul 34 66 52 86 104 143 Aug 32 63 51 67 97 138 Sept 29 58 44 52 89 118 Oct 23 49 38 41 53 52 Nov 20 32 24 25 46 29 Dec 14 14 14 16 46 28 *HB-highbush RE-rabbiteye V. D. Additional Management – Description and BMP Documentation

Additional Management Description

IFAS: Weed Management in Blueberry (HS90)

NRCS: Precision Land Forming Conservation Practice Standard (462)

IFAS: Cover Crops (SSAGR66)

V.D. ADDITIONAL MANAGEMENT CONSIDERATIONS - DESCRIPTION Altos Rock, LLC

Weed Management:

IFAS and/or NRCS recommendations will be followed for chemical weed control for blueberries grown in Florida. Label directions will be read and followed carefully and exactly when applying any herbicides. The herbicides applied to the soil/substrate will be based on the plant type and growth stage. Turf grasses established on drive middles will be mowed regularly and mowing equipment cleaned to prevent the spread of weeds.

Precision Land Forming and Smoothing: Removing irregularities on the land surface improves surface drainage, provides for more uniform cultivation, and improves equipment operation and efficiency. This practice improves surface drainage and controls erosion. Construction operations are to be carried out in such a manner that erosion and air and water pollution are avoided or minimized to the greatest extent practicable.

Vegetative Cover/Plantings: A permanent vegetative cover will be maintained on the exposed middles to avoid erosion by wind and/or water. These areas will be fertilized, mowed and/or irrigated only as needed to maintain a stand. The cover planting will typically be Bahiagrass or Bermudagrass. HS90

Weed Management in Blueberry1 Peter J. Dittmar and Jeffrey G. Williamson2

Blueberry growers use a system of turf and weed-free strips that are currently producing fruit. Nonbearing bushes are under the bushes. A weed-free zone under the bushes blueberry bushes that will not produce fruit for a year after reduces the impact of weeds on blueberry bush growth. For application. The tables include preharvest intervals (PHI). the first 2–3 years, a strip 2–3 ft. wide is maintained weed free. After 3 years, the weed-free strip is widened to 4–5 ft. All herbicides should be directed to the base of the Turf strips are mowed or growth is chemically controlled on bushes; this method provides coverage of the weeds while a regular basis. The turf minimizes erosion and provides an minimizing the contact to the bushes. Young bushes should area for machinery and picking crews. be protected with nonporous wraps or growth tubes to minimize uptake of the herbicide. This is especially impor- Nonchemical weed management practices are part of a tant for systemic postemergence herbicides (for example, complete weed management program. Cultivation was once glyphosate) and contact burndown herbicides (for example, a common practice for weed management in blueberries. paraquat, diquat, and glufosinate). This management practice is not as widely used now because of bush root pruning, erosion, and reduced radiant Tank mixing can broaden the spectrum of weed control. heat in the spring. Reduce the spread of weed species by A preemergence herbicide may only control the most controlling the plants before seeds are produced and by problematic weed in the orchard and leave some weed cleaning mowing equipment. Polyethylene or landscape species unaffected. A preemergence herbicide can be tank fabric mulches provide weed control but can be cost mixed with another preemergence herbicide that controls prohibitive. several weed species but not the most problematic weed in the orchard.

Chemical Control The most common method of tank mixing is a poste- Herbicides available for weed control in blueberry are mergence herbicide with a preemergence herbicide. This included in Tables 1 and 2. Because soil types in Florida method provides control of the weeds that are above the vary, consult the labels for application rate restrictions soil surface and controls weeds for a longer period. Consult based on soil type. Bearing bushes are blueberry bushes the label for compatible tank mixing partners. If concerned,

1. This document is HS90, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date October 1993. Revised February 2012 and June 2015. Visit the EDIS website at http://edis.ifas.ufl.edu.

2. Peter J. Dittmar, assistant professor; and Jeffrey G. Williamson, professor, Horticultural Sciences Department, UF/IFAS Extension, Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication do not signify our approval to the exclusion of other products of suitable composition. All chemicals should be used in accordance with directions on the manufacturer’s label. Use pesticides safely. Read and follow directions on the manufacturer’s label.

1) Herbicide selection. Preemergence herbicides control 1) Rotate herbicide’s mode of action. Each herbicide’s the weeds before they emerge from the seed or break the mode of action (MOA) is assigned a numerical group. soil surface. Postemergence herbicides control weeds that Tables 1 and 2 list the MOA for each herbicide. Rotate have emerged through the soil surface. between modes of action/numerical groups.

2) Optimal timing. Preemergence herbicides should be ap- 2) Include multiple MOA. Many herbicides allow for tank plied in the early spring or fall before annual weeds emerge. mixing herbicides. It is often suggested that preemergence Postemergence herbicide efficacy decreases as weeds grow. herbicides be tank mixed with a postemergence herbicide. Consult the label for the correct size of weed to control. This method controls weeds that will emerge as well asboth weeds that have already and have not yet emerged. 3) Sufficient coverage. Herbicide labels require certain nozzle types or applications of a certain number of gallons 3) Managing known resistance. If an area of the field is per acre (GPA) or nozzle types forto ensure proper cover- known to have a resistant weed species, use mechanical age. Before spraying, check that all nozzles have a correct weed removal and prevent the weed from producing seeds spray pattern and correct output. or other methods of propagation or otherwise propagating itself. Please contact your county Extension agent to have 4) Adequate activation. Preemergence herbicides require the weed resistance confirmed and documented. rainfall or irrigation to move the herbicide into the soil profile where the weed seeds are present. Postemergence herbicides require a nonionic surfactant, crop oil concentrate, or methylated seed oil for increased herbicide uptake.

Weed Management in Blueberry 2 Table 1. Preemergence chemical weed control in highbush blueberry Common Trade name MOA Crop age Comments name (product/acre) (lb. a.i./acre) Dichlobenil (Casoron®) 4 G 20 Bearing / • Annual and some perennial weeds 4–6 100–150 lb. nonbearing • Casoron® 1.4 CS must be applied to well-established plantings and 1.96–3.9 (Casoron®) 1.4 CS not until at least 1 year after transplanting. Casoron® 4 G can be applied 1.4–2.8 gal. 4 weeks after transplanting. Higher rates may be required to control perennial weed species. Diuron (Diuron, Karmex®, 7 Bearing / • Annual broadleaf and grass weeds 1.2–1.6 Karmex® XP) 80 nonbearing • Bushes must be established at least 1 year from transplanting. Direct WDG spray solution to the base of the bush to minimize contact with leaves, 1.5–2.0 lb. flowers, and fruits. Diuron may be applied as a single application in the (Direx®) 4 L spring (1.2–1.6 lb. a.i./acre) and another application (1.2–1.6 lb. a.i./acre) 1.2–1.6 qt. in the fall. Flumioxazin (Chateau®) 51 WDG 14 Bearing / • Annual broadleaf and grass weeds 0.188–0.38 6–12 oz. nonbearing • Direct spray solution to the base of the bush. Do not apply to bushes less than 2 years old unless protected by a nonporous wrap, grow tubes, or waxed cylinders. Do not apply between bud break and final harvest. Do not apply more than 12 oz. in a 12-month period. Do not apply more than 6 oz. per application to bushes less than 3 years old in soils with sand plus gravel content greater than 80%. Do not allow Chateau® to come in contact with any green tissue, or injury may occur. Chateau® may be applied in sequential applications, but not within 30 days of each other. Isoxaben (Gallery®, Gallery® 12 Nonbearing • Certain broadleaf weeds 0.5–1.0 T&V) 75 DF • Allow 60 days between applications and do not apply more than 4 lb. 0.66–1.33 lb. product within a 12-month period. Isoxaben + (Snapshot®) 2.5 TG 12 + 3 Nonbearing • Certain broadleaf and annual grass weeds. Oryzalin 100–200 lb. • A single rainfall or sprinkler irrigation of 0.5 in. is necessary within 3 2.0–4.0 + days of application for optimum +weed control. Allow 60 days between 0.5–1 applications of 150 lb. product/acre or greater. Do not apply more than 600 lb./acre product within a 12-month period. Do not apply to bushes that have wet foliage from rainfall or dew. Mesotrione (Callisto®) 4 L 27 Bearing / • Annual broadleaf weeds 0.09–0.19 3–6 fl. oz. nonbearing • Apply before prebloom, or illegal residues may occur. Can be applied as a split application of 3 oz. followed by 3 oz. with no less than 14 days between applications. Limit contact with green foliage and stems, or injury may result. Include a crop oil concentrate at 1% v/v. The University of Florida has conducted limited testing; thus, any application should be made on a small acreage first to determine cultivar tolerance. Napropamide (Devrinol®) 50 DF 15 Bearing / • Small-seed broadleaf and annual grass weeds 4 8 lb. nonbearing • Do not apply within 1 year of planting. Direct spray solution to the (Devrinol®) 10 G base of the bush to minimize contact with foliage and fruit. Applications 40 lb. should be made to a weed-free surface. Napropamide should be cultivated or irrigated to a depth of 2 in. within 24 hours of application. Norflurazon (Solicam®) 80 WDG 12 Bearing / • Small-seed broadleaf and annual grass weeds 2–4 2.5–5.0 lb. nonbearing • PHI 60 days • Consult label for amount of formulation based on soil texture. Do not apply within 6 months of planting. Rainfall or irrigation is required within 4 weeks of application. Oryzalin (Oryzalin, Surflan®) 3 Bearing / • Certain broadleaf and annual grass weeds 2–4 4 AS nonbearing • Irrigation or rain event of 0.5–1 in. is required within 1 week of 2–4 qt. application. Pronamide (Kerb®) 50 W 3 Bearing / • Certain broadleaf and grass weeds 1–2 2–4 lb. nonbearing • Apply in the fall or early winter when temperature is less than 55°F for maximum efficacy. Do not apply to newly planted bushes; wait for root establishment. Immediately follow application with rainfall or irrigation for additional weed control. Do not apply more than 4 lb. product/acre or more than one application in 1 year.

Weed Management in Blueberry 3 Common Trade name MOA Crop age Comments name (product/acre) (lb. a.i./acre) Simazine (Princep®) 90 WDG 5 Bearing / • Annual broadleaf and grass weeds 2–4 2.2–4.4 lb. nonbearing • Do not apply more than 1 lb. a.i./acre on plantings less than 6 months (Princep®) 4 L old. Apply half the maximum in the spring before bud break and half in 2–4 qt. the fall. Terbacil (5) (Sinbar®) 80 WP 5 Bearing / • Annual broadleaf and grass weeds 0.4–1.6 0.5–2 lb. nonbearing • Only apply to bushes that have been planted for 1 year or longer. Do not use in soils with less than 3% organic matter. Use in the spring or after harvest before weeds emerge or shortly after.

Table 2. Postemergence chemical weed control in highbush blueberry Common name Trade name MOA Crop age Comments (lb. a.i./acre) (product/acre) Carfentrazone (Aim®) 2 EC 14 Bearing / • Broadleaf weeds 0.016–0.031 1–2 fl. oz. nonbearing • Direct spray solution to the base of the bush to minimize contact (Aim®) 1.9 EW with green stems, leaves, flowers, and fruits. Coverage is essential; use 1–2 fl. oz. a minimum of 20 gal. of spray solution per acre. Include a nonionic surfactant, methylated seed oil, or crop oil concentrate; see label for rate. Do not apply more than 0.031 lb. a.i./acre during the dormant stage, 0.064 lb. a.i./acre during the growing stage, and more than 0.096 lb. a.i./acre per crop season. Clethodim (Select Max®) 2 EC 1 Bearing / • Annual and perennial grass weeds 0.07–0.13 9–16 fl. oz. nonbearing • The spray solution should include a nonionic surfactant at 0.25% v/v. Do not apply within 14 days of harvest. Diuron (Diuron, Karmex®, or 7 Bearing / • Annual broadleaf and grass weeds 1.2–1.6 Karmex® XP) 80 WDG nonbearing • Bushes must be established at least 1 year from transplanting. 1.5–2 lb. Direct spray solution to the base of the bush to minimize contact (Direx®) 4 L with leaves, flowers, and fruits. Diuron may be applied as a single 1.2–1.6 qt. application in the spring (1.2–1.6 qt./acre) and another application (1.2–1.6 qt./acre) in the fall. Read labels for restrictions on soil type. Include surfactant at 0.25% v/v or crop oil concentration at 1.0% v/v to improve postemergence weed control. Diquat (Diquat) 2 L 22 Nonbearing • Broadleaf and grass weeds 0.7–0.9 1.5–2.0 pt. • Direct spray to the base of the bush to minimize contact with green stems and foliage. Include a nonionic surfactant at 0.06%–0.5% v/v. Fluazifop (Fusilade® DX) 2 EC 1 Nonbearing • Annual and perennial grass weeds 0.25–0.375 16–24 fl. oz. • Include nonionic surfactant at 0.25%–0.5% v/v or crop oil concentrate at 1% v/v. Glufosinate (Rely® 280) 2.34 SL 10 Bearing / • Broadleaf and grass weeds 1.0–1.5 48–82 fl. oz. nonbearing • PHI 14 days • Does not control goosegrass. Efficacy is reduced when temperatures are cool or when weeds are under drought stress. Direct spray solution to the base of the bush to minimize contact with leaf, flower, and fruit tissue. Do not apply to green or noncallused stems unless protected by nonporous wraps, grow tubes, or waxed containers. Do not apply more than 3 lb. a.i./acre. Glyphosate (Various formulations) 9 Bearing / • Broadleaf and grass weeds 0.5–1.5 nonbearing • PHI 14 days • Direct spray solution to the base of the bush to minimize contact with green stems, leaves, and fruits. Halosulfuron (Sandea) 75DF 2 Bearing / • Broadleaf and sedge weeds 1 to 4 yr. bushes nonbearing • PHI 14 days 0.5-0.6 oz. • Avoid contact with green tissues and leaves. Do not apply to bushes >4 yr. bushes less than 1 year old. Minimum of 45 days between applications. Do 0.5 to 1 oz. not apply more than 2 oz./acre per 12 mo. period. Cultivar tolerance is variable. ‘Emerald’ and ‘Jewel’ are more tolerant. Some growers have reported ‘Prima Donna’, ‘Scintilla’, and ‘Springhigh’ are less tolerant.

Weed Management in Blueberry 4 Common name Trade name MOA Crop age Comments (lb. a.i./acre) (product/acre) Mesotrione (Callisto®) 4 L 27 Bearing / • Annual broadleaf weeds 0.09–0.19 3–6 fl. oz. nonbearing • The University of Florida has conducted limited testing; thus, any application should be made on a small acreage first to determine cultivar tolerance. Apply before prebloom, or illegal residues may occur. Can be applied as a split application of 3 oz. followed by 3 oz. with no less than 14 days between applications. Include a crop oil concentrate at 1% v/v. Limit spray contact with green foliage and stems, or injury may result. Paraquat (Gramoxone Inteon®) 22 Bearing / • Broadleaf and grass weeds 0.56–1 2 SL nonbearing • Direct spray to the base of the stem. Use a coarse spray and hooded 2–4 pt. sprayer to minimize contact with foliage. New canes or shoots can be (Firestorm®) 3 SL injured. Include a nonionic surfactant at 0.125%–0.25% v/v or crop oil 1.3–2.7 pt. concentrate at 1% v/v. Pelargonic Acid (Scythe®) 27 Bearing / • Broadleaf and grass weeds 3%–10% v/v nonbearing • Contact herbicide that should be applied with a shielded sprayer and direct spray to the base of the bush to minimize contact with green tissue. Rimsulfuron (Matrix®) SG 2 Bearing / • Broadleaf and nutsedge weeds 0.063 4 oz. nonbearing • PHI 21 days • Apply after the bushes have gone through one growing season. Application after bud break may cause temporary chlorosis and/or stunting of leaves. Do not apply more than 4 oz./acre per year. New label and should be trialed on a small area before apply to the entire field. Sethoxydim (Poast®) 1.5 EC 1 Bearing / • Annual and perennial grass weeds 0.3–0.5 1.5–2.5 pt. nonbearing • PHI 30 days • Consult label for exact rate to control specific grass species. Multiple applications may be necessary to control perennial grasses, such as bermudagrass. Include a crop oil concentrate at 1 qt./acre.

Weed Management in Blueberry 5 462 - 1

NATURAL RESOURCES CONSERVATION SERVICE CONSERVATION PRACTICE STANDARD

PRECISION LAND FORMING (Ac.)

CODE 462

DEFINITION purpose, they must be included in the plans for improvement. Precision Land Forming is reshaping the surface of land to planned grades. Slope Requirements. Slope may be uniform in the direction of flow or may increase or PURPOSE decrease. This practice improves surface drainage and Reverse grades in the direction of planned controls erosion. water flow must not be permitted. Short level sections are permissible to meet field CONDITIONS WHERE PRACTICE APPLIES conditions. Depending on cultural practices, cross slopes must be such that water can be This practice applies to all land where soils will contained within the furrows to prevent be of sufficient depth and of suitable textures breakthroughs from rainfall runoff. so that after completing precision land forming, an adequate root zone remains to permit the Slope to Control Erosion Caused by Runoff planned use of the land and the application of from Rainfall. Design field grades must be proper conservation measures, soil such that erosion caused by runoff from rainfall amendments, and fertilizer. can be controlled within the limits permissible for conservation farming. When benching This standard does not apply to areas needing between land-formed plots exceeds 1 foot, a Conservation Practice Land Smoothing (466) or permanent grassed area or border ridge must Conservation Practice Irrigation Land Leveling be left between the plots to reduce the (464). possibility of gully erosion. CRITERIA Surface Drainage. All precision land-forming systems must include plans for removing or Plan all precision land forming as an integral otherwise providing for control of excess water. part of an overall system to facilitate the conservative use of soil and water resources. Designs must provide field elevations and field grades that will permit proper functioning of the Design and installation must be based on planned drainage facilities. adequate engineering surveys and investigations. If the land is to be formed for Borrow Computations. Excavation and fill more than one purpose, it must be formed to material required for or obtained from such meet the requirements of the most restrictive structures as ditches, ditch pads, and roadways purpose or crop. must be considered part of the precision land- forming design, and the appropriate yardage All forming work must be designed within the must be included when balancing cuts and fills slope limits required for the proposed use and and determining borrow requirements. provide for the removal of excess surface water. If other conservation practices such as grassed waterways, surface field ditches, and filter strips are needed to accomplish the stated NRCS, NHCP Conservation practice standards are reviewed periodically, and updated if needed. To obtain the current version of this standard, contact the Natural Resources Conservation Service. September 2014 462 - 2

CONSIDERATIONS REFERENCES Effects on the water budget, especially on U.S. Department of Agriculture, Natural volumes and rates of runoff, infiltration, deep Resources Conservation Service, Engineering percolation, and evaporation should be Field Handbook, Chapter 1. Surveying. considered. National Engineering Handbook, Part 650.01, Washington, DC. Short-term and construction effects of installation on downstream water resources U.S. Department of Agriculture, Natural should be minimized. Resources Conservation Service, Engineering Potential for earth moving to uncover or Field Handbook, Chapter 4. Elementary Soils redistribute toxic materials, such as saline soils, Engineering. National Engineering Handbook, and make them available to water or plants Part 650.04, Washington, DC. should be addressed. U.S. Department of Agriculture, Natural Consider effects on wetland hydrology and/or Resources Conservation Service, Irrigation wetland wildlife habitat. Land Leveling. Section 15, Chapter 12. Address potential impacts to existing utilities by National Engineering Handbook, Part 623.12. relocating and avoiding all utilities. Washington, DC. Consider effects on soil loss due to increased U.S. Department of Agriculture, Natural wind erosion potential and subsequent Resources Conservation Service, Engineering deposition. Field Handbook, Chapter 14. Water Management (Drainage). National Engineering Handbook, Part 650.14, Washington, DC. PLANS AND SPECIFICATIONS

Plans and specifications for land smoothing must be in keeping with this standard and must describe the requirements for applying the practice to achieve its intended purpose. Plans and specifications must include construction plans, drawings, job sheets or other similar documents. These documents must specify the requirements for installing the practice.

OPERATION AND MAINTENANCE An Operation and Maintenance (O&M) plan must be prepared for and reviewed with the landowner or operator. Actions must be carried out to insure that this practice functions as intended. Such action must include performing maintenance when needed to insure that surface irregularities are maintained at the degree of smoothness required. The plan must specify that the treated areas and associated practices be inspected annually and after significant storm events to identify repair and maintenance needs.

NRCS, NHCP September 2014 SS-AGR-66

Cover Crops 1 Y.C. Newman, D.L. Wright, C. Mackowiak, J.M.S. Scholberg, C.M. Cherr and C. G. Chambliss2

Introduction conventionally, the incorporation of cover crops/green manures into a management plan will provide numerous The use of cover crops dates back over 2,500 years. Several benefits and some challenges. This publication provides ancient Greek and Roman sources suggest growing cover some basic guidelines for the successful use of cover crops. crops to produce green manure for vineyards and other crops. However, during the past century there has been a trend within conventional agriculture to ignore the role of Potential benefits/challenges soil organic matter in crop production, and the use of com- Cover crops can be used for several purposes: mercial chemical fertilizers for agricultural crop production has greatly increased. Although chemical fertilizers are 1. To control weeds since cover crops compete for light, affordable and easy to apply, they don’t add to soil organic water and nutrients; matter. In fact, the gradual decline in soil organic matter associated with continued chemical fertilizer use, particularly 2. To prevent soil losses associated with heavy rainfall (soil in the extremely sandy soils of Florida, makes it difficult to water erosion); maintain crop vigor, yield and quality. 3. To reduce soil losses due to strong winds (e.g. prevent soil Appropriate use of cover crops, on the other hand, may wind erosion and a potential “dust bowl”) and to protect partially replace chemical fertilizer usage and thus, reduce more sensitive crops such as watermelon from sand dependence on fossil fuels and foreign oil. Moreover, cover blasting damage; crops function as slow release fertilizers, thereby reducing excessive nutrient leaching. Their use may also sustain/ 4. To scavenge and retain nutrients that otherwise might be enhance soil organic matter content. This is critical or many lost in water runoff or by leaching during the off-season. Florida soils, especially for sandy soils which typically have This helps reduce fertilizer costs for future crops and also low inherent soil fertility, do not retain much water or protects the environment from problems caused by excess nutrients, and are often prone to excessive nutrient leaching nutrient loading in our water sheds; losses. Whether cash crops are produced organically or

1. This document is SS-AGR-66, one of a series of the Agronomy Department, UF/IFAS Extension. First printed May 1997. Revised November 2010. Reviewed April 2014. Please visit the EDIS website at http://edis.ifas.ufl.edu.

2. Y.C. Newman, assistant professor, Forage Extension Specialist, Agronomy Department, University of Florida; D.L. Wright, professor, Agronomy Department, North Florida Research and Education Center (NFREC)--Quincy, FL, University of Florida; C. Mackowiak, assistant professor, Soil and Water Science, NFREC, University of Florida; J.M.S. Scholberg, postdoctoral associate, Wageningen University, Biological Farming Systems Group; C.M. Cherr, graduate student, Ecology and Department of Plant Sciences, University of California, Davis; C. G. Chambliss, associate professor, Agronomy Department, UF/IFAS Extension, Gainesville, 32611. Originally written by C.G. Chambliss (deceased).

6. To generate supplemental income (e.g. via hay Summer cover crops tend to generate more biomass and production); cool season leguminous crops, on the other hand, require adequate soil moisture, fertility (especially phosphorus), 7. To form a suitable mulch cover for row middles and/or and a suitably high (6.0 – 6.5) soil pH to perform well. mulched beds; These winter season legumes often do not perform well on sandy soils during the first years of cultivation. In contrast, 8. To provide habitat for beneficial birds and insects. many of the warm season annual leguminous crops listed in Table 1 tend to be a little bit more vigorous and require Many cover crops will fulfill several of the above purposes. additional management. For example, a crop that will produce enough growth to outcompete weeds should produce enough herbage to sustain and/or improve soil organic matter content. Cover crop establishment Although cover crops provide many benefits, some may Cover crops are grown in pure or mixed stands. Most also be excessively tall, woody and/or weedy. They can annual cover crops need to be established each year, but also potentially interfere with cultivation or harvesting, some types may reseed naturally (e.g. alyceclover, iron/ while others may harbor pests and diseases. Consequently, clay cowpea, and hairy indigo). Reseeding types may be selection of the right cover crop for a particular situation is preferable for groundcovers in orchard systems since they critical. may reduce replanting cost. However, in other systems they may potentially become weeds and need to be mowed Cover crop classification in a timely fashion to prevent problems. An overview of suggested seed rates is outlined in Table 1. One of the main issues to consider when choosing a cover crop is the season or period in which it will be needed. We Cover crops can be planted in rows spaced 8-24 inches can differentiate between crops that are short-lived (annual apart or broadcasted. Use of more narrow row spacing will cover crops such as winter rye) vs and crops that can hasten initial groundcover and is more effective for weed remain for many years (perennial crops such as bahiagrass suppression. Cover crops may be grown in rotation with and perennial peanut). Annual cover crops can be catego- various cash crops as a temporary or permanent ground rized into two main classes, : 1) crops that are adapted to cover (living mulch) in tree groves and citrus orchards. The cool, short days (winter cover crops such as hairy vetch) advantage of perennial species is that they need to be estab- and 2) those that are adapted to hot, long days (summer lished only once and provide a continuous ground cover. cover crops such as cowpea). We can further differentiate Perennial crops that are propagated asexually by sprigs between grass/grain vs. leguminous type cover crops. An are more expensive unless equipment and plant material overview of available cover crop within each of these groups is available on-farm. Perennial peanut tends to establish and their performance, in terms of herbage (biomass) and slowly and usually take 1-3 years to obtain a satisfactory nitrogen (N) production is presented in Table 1. solid ground cover. Cover crops may be maintained as living mulch, harvested as hay, or incorporated into the Leguminous crops, initially, tend to grow slower than grass/ soil once they have broken down. Depending on the seed grain crops, and may not produce as much seasonal bio- rate and seed cost, establishment costs are on the order of mass (herbage) but they may add between 60-200 lbs N/ac $60-$150/acre and $160-400/acre for annual and perennial per cropping season. Legumes have the ability to symbioti- cover crops, respectively. The use of cover crops is typically cally associate with certain soil bacteria (rhizobia) that fix most cost-effective if one crop fulfills multiple needs. atmospheric nitrogen. Therefore, if an appropriate inocu- lant is used or sufficient symbiotic N-fixing bacteria are present in the soil, no supplemental N fertilizer is necessary Conclusions to produce abundant biomass. Their herbage also tends to One of the key challenges in using cover crops is to maxi- be richer in proteins with no nitrates, and decomposition mize crop nutrient accumulation as well as matching the is more rapid, compared to grass/grain crops. Since legume demands of a succeeding commercial crop to the specific inoculants are readily available and relatively inexpensive, it nutrient release patterns from of a cover crops residues that meet the demands of a succeeding commercial crop. Since

Cover Crops 2 cover cropping was integral to past Florida farming practices, it may be worthwhile to take advantage of the experience and knowledge of older farmers in your region who farm similar soils and have used cover crops successfully. There is no perfect cover crop for each and every situation. Finding the best cover crop to address your specific needs may take some patience and experimentation with different crops, crop combinations, and management practices. However, use of appropriate technological innovations and/ or suitable equipment (e.g. crimpers or flail mowers) and/ or herbicides may facilitate improved cover crop benefits. Use of multiple species can further enhance the adaptability and performance of a cover crop system. This is especially important when growth conditions are less favorable for one of the component species (e.g. poor and variable soil fertility and unpredictable weather conditions). In this case, plant types should be chosen that complement each other rather than compete with each other. The crops listed in Table 1 can supply large amounts of material to contribute to the soil organic matter. A more comprehensive and detailed review of the use of cover crops and green manure can be obtained from the references listed below. Suggested Reading Cherr, C.M., J.M.S. Scholberg, and R. McSorley. 2006. Green manure approaches to crop production: a synthesis. Agronomy Journal 98:302-319.

Y. Li, E. A. Hanlon, W. Klassen, Q. Wang, T. Olczyk, and I. V. Ezenwa. 2006. Cover crop benefits for South Florida commercial vegetable producers. EDIS publication SL242. http://edis.ifas.ufl.edu/pdffiles/SS/SS46100.pdf.

Cover Crops 3 Table 1. Cover crops for use in Florida. Crop Yield - Biomass1 (lbs/acre) Yield - N1 Seeding Rate(lbs/acre) Seeding Date (lbs/acre) ANNUAL SUMMER COVER CROPS Leguminous Crops Aeschynomene 2000 - 4000 50-100 6-82 Mar. 1 - June 30 Alyce clover 1500-3500 20-65 15-20 Mid April to late June Cowpeas 4000 - 6000 50-90 6-82 April to August Hairy Indigo 7 to 10 tons of 80-150 6 - 10 Middle of March to greenchop/acre May/June Sesbania 2000-8000 35-80 25-30 Mar. 1 - July 15 Sunhemp 4500-10,000 90-180 30 - 50 Mar. 1 - June 30 Velvetbeans 2200 - 4000 50-85 30-50 Mar. 1 - June 30 Grain Crops Pearlmillet 6000-8000 55-70 12 to 15 lb/acre in rows, Mid March to June of 30 to 40 lbs/acre if in North Florida, broadcast earliest planting is April 1st. Sorghum-sudan 6500-9500 55-80 24-30 Mar. 1 - June 30 ANNUAL WINTER COVER CROPS Leguminous Cropos Crimson Clover 1500-5000 35-120 20-25 Oct. 1 - Nov. 15 Hairy Vetch 2000-4000 35-150 20-30 Oct. 1 - Nov. 15 Lupine 2000-4500 45-120 30-45 Oct. 1 - Nov. 15 Grain crops Black oats 1500-3500 20-40 80-100 Oct. 1 - Nov. 15 Winter rye 3000-6000 30-50 80-100 Oct. 15 - Nov. 15 PERENNIAL COVER CROPS Leguminous Crops Rhizoma Peanut (living 2000-10000 50-130 80-100bu of rhizomes/acre3 Dec. to March mulch) (12-months) (1 bu=1.25 cubic ft.) Perennial Grasses Bahiagrass 3000-8000 55-140 15-20 Junt to August (if rainfed) Pangola digitgrass 4000-9000 60-135 500-10003 Mar. 1 - Aug. 15 1Lower productivity reflects poor growing conditions (water stress, poor inherent soil poor inherent soil fertility/inoculation) while higher values are indicative of crop performance under optimal conditions. 2Dehulled seed (naked). 3Planted vegetatively.

For additional information, please visit the ‘Forages of Florida’ website at: http://agronomy.ifas.ufl.edu/ForagesofFlorida

Cover Crops 4 VI. Operation and Maintenance

Construction Specifications – Operation and Maintenance

NRCS: Pest Management – O & M

NRCS: Irrigation Water Management (449) – O & M

NRCS: Irrigation System: Microsystem (441) – O & M

NRCS: Construction Specifications for Vegetative Measures

Resource Management Plan - Altos Rock, LLC OPERATION AND MAINTENANCE FOR PEST MANAGEMENT

The pest management component of a conservation plan shall include appropriate operation and maintenance items for the client. These may include:

• Review and update the plan periodically in order to incorporate new IPM technology, respond to cropping system and pest complex changes, and avoid the development of pest resistance.

• Maintain mitigation techniques identified in the plan in order to ensure continued effectiveness.

• Develop a safety plan that includes telephone numbers and addresses for emergency treatment centers for individuals exposed to chemicals and the telephone number for the nearest poison control center

For advice and assistance with emergency spills that involve agrichemicals, the national 24-hour CHEMTREC telephone number is 1-800-424-9300

• Follow label requirements for mixing/loading setbacks from wells, intermittent streams and rivers, natural or impounded ponds and lakes, or reservoirs. (State or local regulations may be more restrictive).

• Post signs according to label directions and/or Federal, State, and local laws around fields that have been treated. Follow restricted entry intervals.

• Dispose of pesticides and pesticide containers in accordance with label directions and adhere to Federal, State, and local regulations.

• Read and follow label directions and maintain appropriate Material Safety Data Sheets (MSDS).

• Calibrate application equipment according to Extension and/or manufacturer recommendations before each seasonal use and with each major chemical change.

• Replace worn nozzle tips, cracked hoses, and faulty gauges.

• Maintain records of pest management for at least two years. Pesticide application records shall be in accordance with USDA Agricultural Marketing Service’s Pesticide Record Keeping Program. See USDA’s publication on Pesticide Record-keeping Requirements. Florida Pesticide Law requires certified applicators to keep records on the applications of Restricted Use Pesticides (RUP). Information on the RUP needs to be recorded within two working days of the application and maintained for two years from the application date. Operation & Maintenance Plan

Irrigation Water Management

Landowner/Operator: Date: NRCS Service Center: Conservation District: Practice Location: Tract/Field ID: (Lat/Long or UTM Coord. or Sec/TS/R)

Operation & Maintenance Requirements

Irrigation water management (IWM) is a practice for your purpose in improving irrigation water use efficiency, minimizing irrigation induced soil erosion, decreasing degradation of surface and groundwater resources, managing salts in the crop root zone, managing air, soil, or plant micro-climate, and/or reduce energy use for your irrigated field(s). The operation and management (O&M) plan requires that you follow the requirements of the IWM Plan. If there are changes in the crops, irrigation system, or management, the IWM will need to be revised to reflect the changes.

• Document all irrigation water management activities and maintain records including, but not limited to, the following:

o Record each irrigation event, including the amount or depth of water applied and the date of application,

o Record the data from the methods(s) used for determining the timing and amount of irrigation event.

Date Crop Root Method Available MAD, Gross irrigation Depth, used to Water % Applied, inches determine Holding Inches MAD Capacity

• Check to ensure O&M items are addressed for the physical components of companion conservation practices applicable to this site.

Type of Irrigation System O&M Check List

Florida NRCS Page 1 of 1 September 2015 Operation & Maintenance Plan

Irrigation System, Microsystem, Code 441

Landowner/Operator: Date: NRCS Service Center: Conservation District: Practice Location: Tract/Field ID: (Lat/Long or UTM Coord. or Sec/TS/R)

Operation & Maintenance Requirements

This microirrigation system was designed and installed to apply irrigation water to meet the needs of the crops without causing excessive erosion or runoff. The estimated life span of this installation is at least 20 years. The life span of this practice can be assured and usually increased by developing and carrying out an operation and maintenance (O&M) program.

You are required to perform inspections and O&M activities in order for this practice to achieve the intended function, benefits, and design life. Items to inspect, operate, and maintain during the estimated design life of this practice include, but are not limited to, the following:

• Check to make sure that all connections are watertight and all valves are working properly.

• Make sure that the filter system is working; even if it is automatic, it needs constant monitoring. Clean filters and make adjustments if needed.

• Periodically examine each emitter for proper operation, replace if defective.

• Exclude all livestock from the equipment and irrigated areas.

• During non-seasonal use, drain and place the removable part of the system in an area where it will not be damaged.

• Immediately repair any vandalism, vehicular, wildlife, or livestock damage.

• Operate irrigation system in accordance to the irrigation water management plan.

Florida NRCS Page 1 of 1 September 2014 CONSTRUCTION SPECIFICATIONS FOR VEGETATIVE MEASURES

1. SCOPE

The work shall consist of preparing the area for treatment, furnishing and placing seed, sod, mulch, fertilizer and lime as specified in the designated areas.

2 . MATERIALS

Seed used shall be in accordance with the rules and regulations under each Florida Seed Laws. Each container of seed shall be labeled as follow a. lot number b. name of the kind or kind and variety c. percentages of pure seed, other crop seed, weed seeds, and inert matter d. percentage of germination, and hard seeds (if any) e. date tested (month and year) f. names and number per pound of noxious weed seed g. name and address of shipper

All seed shall be furnished in sealed standard containers, unless exception is granted in writing. Seed shall be thoroughly re-cleaned, and of uniformly good quality and appearance throughout each container. Seed, which has become wet, moldy, or otherwise damaged in transit or in storage will not be acceptable. Each lot of seed shall be subject to sampling and testing. The seed shall contain no prohibited noxious weed seed. The total number of all restricted noxious weed seed shall not exceed 300 per pound. Method of scarification shall be mechanical. Seeds shall conform to the quality requirements as shown in the following table.

NRCS-FLORIDA 1 04/01110 Minimum Minimum percent Name of seed percent germination and or mixture pure seed hard seed Argentine bahiagrass (50% scarified) 80 70

Hulled Common Bermudagrass 95 85 Rye 97 85 Browntop millet 98 85 Oats 98 90 Wheat 99 90 Argentine bahiagrass, Bermudagrass and a nurse crop of oats, rye, or wheat shall be used if planting is done between September and February. Argentine bahiagrass, Bermudagrass and a nurse crop of browntop millet, pearl millet, Japanese millet or pioso millet shall be used if the seeding is done between March and August. Sod shall be Argentine Bahiagrass and shall be l2-inch by l2-inch squares or other commercially available rectangles. The sod shall be sufficiently thick (minimum thickness of 2 inches) to provide a dense stand of live grass. The sod shall have been grown on mineral soil. Sod shall be live, fresh, and uninjured at the time of planting and shall be protected from drying out by shading and watering from the time it is dug until planting. Mulch materials, where seeding and mulching will be done, shall be wheat or oat straw or other plants approved by the Engineer. The mulch material shall be air dry, and shall not be musty, moldy, caked, or otherwise of low quality. The mulch material shall be free of seeds of competing plants and noxious weeds. Fertilizer shall be either in the liquid or dry form. Fertilizer shall be uniform in composition, free-flowing and suitable for application with standard equipment. The fertilizer shall conform to the Florida Fertilizer Laws in effect on the date of it being placed and shall be delivered in bags, bottles, drums, or other convenient containers, each fully labeled and bearing the name, trademark, analysis, and warranty of the product. Fertilizer shall have an available plant food analysis of 10-10-10 or equivalent plant food value and shall be mixed with the top 3 to 4 inches of soil. Lime shall be Dolomitic limestone, and shall be in accordance with rules and regulations of Florida Fertilizer Law in effect on the date of it being placed.

NRC'S-FLORIDA 2 04/01110 . ~. ~ ~ ~ Staples for sod placed on side slopes steeper than 3:1 shall be black :".; iron wire not smaller than 14 gauge, and bent from a length of wire at :".; least 25 inches long into a 'u' with a 1 inch width at the crown. ;,.) Water used for irrigation may be obtained from any approved source. ~ It shall be free of excess and harmful chemicals, acids, alkalies, or any substance, which is harmful to plant growth. :".; ;.> 3 . SITE PREPARATION ~ Site preparation shall include preparing seedbeds to a depth of 3 to 4 :".; inches. Fertilizer and lime shall be uniformly spread over the area and incorporated to a depth of 3 to 4 inches. Fertilizer shall be ~ applied at the rate of 800 pounds per acre or 18 pounds per 1000 :.,,; square feet. Lime shall be applied at the rate of one ton per acre or 45 pounds per 1000 square feet. ;,.) Where sodding will be done, all loose rock, woody material, and other :".; obstructions that will interfere with sodding shall be removed and the :".; area be reasonable smooth and uniform. Lime and fertilizer will be applied in the same quantity and manner as for seeding. :".; ~ 4 . VEGETATIVE TREATMENT ~ Vegetative treatment required by this specification shall consist of '..; performing the items specified in the manner designated below. ;.; Seedinq shall consist of site preparation and seeding at the rates and '.,) manner described in this specification. All disturbed areas not sodded will be seeded. ~ :..; The seeding rate shall be: ~ Bahiagrass 30 pounds per acre or 0.7 pounds per 1000 sq. ft and ;.,; Hulled Common 10 pounds per acre ., Bermudagrass Rye 1 bu. per acre or - Oats 2 bu. per acre or Wheat 1 bu. per acre or Browntop millet 30 pounds per acre or 0.7 pounds per 1000 sq. ft

The seed shall be uniformly spread over the area and covered 1/2 to l inch deep.

NRCS-FLORIDA 3 04/01110 Mulching will be performed after the seeding has been done, uniformly spread 2 tons of mulch per acre over the area so that 25 percent of the ground surface is visible. The mulch shall be anchored into the soil which may be done by cutting the mulch to a depth of 3 inches with a disc set almost straight or other similar method acceptable to the NRCS technician. Approximately one-half of the mulch material shall be above the soil surface. The area shall be firmed with a cultipacker, roller, or other equipment approved by the NRCS technician. The mulch anchoring and firming of the soil may be done in one operation if good workmanship is accomplished and it is approved by the NRCS technician.

Sodding shall consist of site preparation, sodding and irrigating at the rates and manner described in this specification.

The sod strips shall be laid in a staggered pattern with snug even joints. All joint shall be butted tight to prevent voids. Immediately following sod placement, it shall be rolled or tamped to insure solid contact of root mat to soil surface. The sod shall be securely anchored to the soil by pinning with staples or wooden pegs when placed on slopes steeper than 3:1. Pin or peg every 3 feet along each strip of sod.

5. IRRIGATION REQUIREMENTS FOR SOD

All areas to be sodded shall be irrigated with ~ inch of water prior to placement of the sod if soil moisture is deficient

6. CONSTRUCTION DETAILS a. Engineering drawings for Diane Starling. b. All disturbed area shall be immediately vegetated.

NRCS-FLORIDA 4 04/01/10