2019 Pest Management Guide for Grapes in Washington

WASHINGTON STATE UNIVERSITY EXTENSION • EB0762 EB0762 Pest Management Guide for Grapes in Washington—2019

POISON EMERGENCY Washington Poison Center: 1-800-222-1222 https://www.wapc.org/ For further information, see Pesticide Safety

PESTICIDE LABELS YOU ARE REQUIRED BY LAW TO FOLLOW THE LABEL. It is a legal document. Always read the label before using any pesticide. You, the grower, are responsible for safe pesticide use.

Trade Names Trade (brand) names are provided for your reference only. No discrimination is intended, and other pesticides with the same active ingredient, provided they are also registered for use on the intended crop and for the intended target, may be suitable. No endorsement is implied.

Pesticide Information National Pesticide Information Center: 1-800-858-7378 http://npic.orst.edu/

Spray Guide Coordinators Gwen Hoheisel, Regional Extension Specialist Michelle Moyer, WSU Extension Viticulturist

Front Cover Photos Michelle Moyer, WSU Extension Viticulturist

SECTION COORDINATORS: Regulations & Safety Carol Black, WSU Pesticide Education Specialist

Pesticides Catherine Daniels, WSU Pesticide Coordinator

Weeds Lynn Sosnoskie, WSU Extension Weed Specialist Tim Miller, WSU Extension Weed Specialist

Insects Douglas Walsh, WSU Extension Environmental and Agrichemical Education Specialist Gwen Hoheisel, Regional Extension Specialist

Nematodes Inga Zasada, USDA-ARS Research Plant Pathologist

Plant Diseases Michelle Moyer, WSU Extension Viticulturist Naidu Rayapati, WSU Extension Grape Virologist

Prepared by representatives of Washington State University, WSDA and USDA personnel, and industry representatives.

WSU Extension • Washington State University • Pullman, Washington CONTENTS

General Information...... 1 Pest Management Program for Grapevines...... 24 Pesticide Safety...... 1 Precautions in Use and Storage Diseases of Grapevines...... 29 Pesticide Disposal and Plastic Container Trunk and Root Diseases Recycling Foliar and Fruit Diseases Symptoms of Pesticide Poisoning Protections, Emergency Treatment, and Disease Management Program for Pesticide Information Grapevines...... 35

Weed Control...... 4 Viruses of Grapevines...... 44 Application Rate and Equipment Management of Grapevine Virus Diseases General Precautions Grapevine Leafroll Disease Factors Affecting Control Rugose Wood Complex (Grafted Vines) Soil-Applied Herbicides Grapevine Fanleaf and Grapevine Decline Foliar-Applied Herbicides Diseases Grapevine Red Blotch Disease Herbicide Injury...... 14 Potential Virus Diseases 2,4-D Drift Documentation Spray Recommendations ...... 48 Weed Management Program General for Grapevines...... 15 Formulations Calibration of Vineyard Sprayers Pests of Grapevines...... 17 Dilutions Black Vine Weevil Brown Marmorated Stink Bug Regulatory Information...... 51 Cutworms Pesticide Residues on Grapes Drosophilla suzukii Pesticide Restricted Entry Standards Grape Flea Beetle Licensing Grape Leaffolder Chemigation Grape Mealybug State Laws and Regulations Grape Phylloxera Worker Right-To-Know Act Leafhoppers Horticulture Pest and Disease Boards Mites Tank Mixes Plant-Parasitic Nematodes Scale Insects Thrips

GENERAL INFORMATION

The Pest Management Guide for Grapes in Washington LABEL and be certain that it is up to date. presents various chemicals and their uses against pest problems in Washington vineyards. While Always consult with your processor, winery rep- the recommendations are based on eastern resentative, or Extension agent if you have any Washington conditions, the information may questions on approved pesticides or pesticide uses. often be applied to similar pest problems found The registration status of various chemicals, for- throughout the state. Specific and more detailed mulations, and manufacturers’ products changes information on pests and diseases can be found rapidly. You may lose your crop or market if you in the Field Guide for Integrated Pest Management in misapply or use improper materials that leave ille- Pacific Northwest Vineyards (PNW644). gal residues on your crop.

Recommendations are suggested guidelines. Pests Not on Product Label: Some suggested They are not intended to represent pest control uses of pesticides in this publication are for pests programs. The use of other materials and varying not listed on product labels. These are indicated by rates and treatments for control of particular pests the symbol '*'. Such uses comply with the federal depends on individual circumstances. law (FIFRA), which says a use is consistent with label directions provided the crop or site is on the Caution: Before making any application of chemi- label and directions concerning rates and interval cals to any vineyard, READ THE COMPLETE before harvest are followed.

PESTICIDE SAFETY

Precautions in Use and Storage providing emergency transportation for any exposure of concern. The web site http:// • Know the trade names and active ingredients pesticideresources.org has WPS resources to for the pesticides you are using. Be famil- assist grower’s understand their responsibili- iar with the first aid treatments, especially ties and has training information and tools. anything unique, before you store or handle pesticides. • Pesticide labels state the personal protective equipment (PPE) to be worn when handling/ • To protect your workforce, comply with the applying pesticides. At a minimum, long US EPA Worker Protection Standard (WPS) that is administered by Washington Depart- sleeved shirt and long pants are required ments for Agriculture and Labor & Industries. to protect your skin from exposure; usually WPA classifies employees asworkers if they waterproof gloves too. If there is an added could be exposed while working in vineyards risk due for the product, the label may that were treated in the past 30 days. Or clas- require a coverall be worn over short sleeved sifies employees aspesticide handlers if they shirt/short pants or long sleeved shirt/long mix, load, apply, or conduct maintenance pants. The coverall can be a standard cotton on application equipment because they have or cotton polyester coverall; some opt for the possibility of direct exposure to pesticides a disposable coverall to reduce laundering while working. Agricultural pesticide labels hassles. To protect eyes, wear safety glasses state a Restricted Entry Interval (REI) for each with brow and side covers, a face shield, or crop. This REI is a time when no entry is goggles. Waterproof gloves and boots may be allowed into the treated area, unless the per- required; reusable nitrile gloves meet most son is provided extra protection as detailed label requirements. Lastly some products in the regulations and on the label. The may require a respirator to filter out particu- section of the label that addresses WPS is the lates or vapors/gasses from contaminated air. Agricultural Use Requirements section. The reg- Obtain a NIOSH-certified respirator, and if ulation requires notifying employees about needed, the appropriate chemical cartridge pesticides applied, training those employees, (most often an organic-vapor cartridge). monitoring the handling of highly toxic Dispose of any PPE that cannot be cleaned. pesticides, providing handlers clean PPE, and Wash all other PPE at the end of the task.

1 • Be aware of heat illness. By wearing PPE, • Collect spilled material and absorbent for your body does not cool as well. Washing- later use or hazardous waste disposal. Wash ton Labor & Industries has Outdoor Heat the contaminated area with soap and water. Exposure regulations for agriculture (WAC The breakdown of insecticides can be acceler- 296-307). It sets thresholds at 89°, 77°, and ated by using a weak lye solution. 52° depending on the number of layers of • Most pesticide labels prohibit applications clothing a person is wearing and if the layer during temperature air inversions. Inver- is non-breathable, like a rain suit. Acclimati- sions happen typically in the late afternoon zation, drinking water, and illness awareness as the air cools and settles, then lasts through are the main requirements. Schedule pesti- the night and early morning. It does not cide applications during the cooler parts of dissipate until the sun warms the soil the the day. next day and air starts to move around • Some insecticides are organophosphates or again. During an inversion, air cannot mix carbamates. They have caused poisonings vertically, and spray particles may be carried in Washington from unintended exposures horizontally for a great distance. New inver- during routine tasks. If either type of insec- sion meters are available to assess conditions. ticide product has the signal word of Warn- Unfortunately to combat the concerns for ing, Danger/Poison or Danger and they are heat stress, the coolest time of the day is best handled (mix, load, apply) for more than 30 to apply—just make sure there is no inversion. hours in a 30 day period, the Washington • Cover or remove food and water troughs Dept. of Labor & Industries (WAC 296-307- when spraying around livestock areas. Avoid 148) requires a medical monitoring program. contamination of fishponds, irrigation This is a blood testing protocol to monitor canals, streams, and lakes. Check wind direc- for exposures to reduce the chance on an tion often when applying in sensitive areas. accidental poisoning and to assist with treat- • Avoid drift of pesticides to other crops. ment. A pre-season blood test determines Again, check wind direction often. Check your normal cholinesterase activity level. equipment function, particularly look for If symptoms occur, seek medical treatment leaks and malfunctioning nozzles. immediately and they will retest your levels. There are antidotes to treat a poisoning; • Given changing wind conditions, plan your however, they are only administered by a application to keep the spray moving away medical professional. from you and if the wind changes, change your strategy. • Keep soap and water available for emergency decontamination for an unexpected expo- • Pesticides that persist for long periods of sure, such as from a broken hose. time in the soil may injure susceptible crops planted the following year and may result • Before recycling or disposal, triple-rinse in illegal residues. Observe label restrictions containers and pour rinsate into the spray concerning the intervals and crops which mixture you are making up. Puncture rinsed may be grown in treated soils. containers to ensure they cannot be reused. • Some pesticides may cause plant injury Offer rinsed plastic containers for pesticide under certain conditions or on certain variet- container recycling (see next section). Wash- ies. Be sure the material is recommended for ington State does not allow burning of used use on the plant to be treated and that condi- pesticide containers. tions are favorable for application. • Keep your pesticide storage area locked. Keep • Some processors may not accept a crop used, empty, triple rinsed pesticide contain- treated with certain pesticides. If crops are ers in your storage area. going to a processor, be sure to check with • Do not use your cell phone, smoke, chew their field representative before applying tobacco, or eat while spraying or while your pesticides. hands are contaminated with concentrate • When a permanent vineyard crop cover has products or a spray batch. flowers, the cover must be mowed before • Mix pesticides according to label directions spraying insecticides that are toxic to bees, and apply at the recommended rate. and to protect all pollinators.

2 Pesticide Disposal and labels for PPE (gloves, protective eyewear, coveralls, Plastic Container Recycling respirators, etc.). Neurotoxic insecticides include organophosphates and carbamates, and the symp- Most pesticide products become classified toms of acute poisoning develop within minutes to hazardous waste upon disposal and fall under the hours after exposure. Most commonly reported ear- Washington State Dangerous Waste Regulations, ly symptoms include headache, nausea, dizziness, Chapter 173-303 WAC, which is administered sweating, salivation, tearing, and nasal discharge. by the Washington State Department of Ecology. Muscle twitching, weakness, tremor, incoordina- The regulations are complex. A grower who needs tion, vomiting, abdominal cramps and diarrhea to dispose of pesticide formulations or excess signal more severe poisoning. tank mix should contact the appropriate regional Ecology office for guidance. Northwest Regional Office (Bellevue): Protections, Emergency Treatment, and 425-649-7000 Pesticide Information Southwest Regional Office (Lacey): Good hygiene is important to reduce exposures. 360-407-6300 Wash your hands and face when done with a Central Regional Office (Yakima): task, and shower at the end of the day. Wear clean 509-575-2490 clothes and PPE each day. Wash contaminated Eastern Regional Office (Spokane): clothing separate from the family laundry. 509-329-3400 Call the National Poison Center at 1-800-222-1222 The Washington State Department of Agriculture’s for emergency information if an exposure occurs; Waste Pesticide Program collects and disposes of they are staffed 24-hours a day. The person answer- unusable pesticides owned by agricultural producing your call will refer you to the nearest hospital ers. This program depends on state funding. Sev- handling pesticide poisonings. eral collections are held throughout the state each year. Contact 1-877-301-4555 or visit their web Emergency First Aid Basics—reference the pesticide site: http://agr.wa.gov/pestfert/pesticides/wastepes- label. ticide.aspx. l. Reduce the exposure immediately when it Triple-rinsed, plastic pesticide containers, large and occurs. small, are collected by the ACRC (Ag Container a. Remove contaminated clothing, wash the Recycling Program) contractor, which is currently affected area, then put on clean clothes. Agri-Plas in Oregon; http://agriplasinc.com. They provide collection and processing services for triple b. Move to fresh air when pesticides are in or pressure-rinsed plastic pesticide containers. They your air space. offer mobile grinding and whole container pickup, c. Rinse eye for 15 minutes if material and have a pickup schedule on their web site. enters the eye. 2. If breathing stops, the most important first Symptoms of Pesticide Poisoning aid is artificial respiration. Make sure first responders take care to avoid exposure while Herbicides and fungicides can result in skin, eye, performing first aid. or throat irritation. Redness or rashes are the most common poisoning systems. Some surfactants 3. Never try to give anything by mouth to an in herbicides are similar to soaps and can irritate unconscious person. or damage eyes. Read labels and wear noted PPE Lastly, another resource for getting answers to (gloves, protective eyewear, respirators, etc.) to pro- questions about safety issues related to pesticides tect skin and eyes, and prevent inhalation. is the National Pesticide Information Center, Many insecticides work on the human nervous sys- http://npic.orst.edu, or call 1.800.858.7378 tem the same way they do on insects; it’s the dose between 8:00 AM to 12:00 PM Pacific Time, that makes the poison. They can enter through Monday through Friday. You can always email eyes or skin or by ingestion or inhalation. Read them as well at [email protected].

3 WEED CONTROL

Weeds can directly compete with grapevines To reduce the hazard of injury to vines as well for water, nutrients, and light. Weeds may also as to ensure the maximum effectiveness of the impact vines indirectly, by serving as alternate herbicides applied, select your equipment and its hosts for insect pests and pathogens; providing use carefully. Herbicides need to be applied with a habitat for rodents; altering the distribution of fixed boomtype applicator equipped with flat, fan- irrigation water; interfering with the deposition type nozzles. The height of the boom depends on of pesticides; and impeding the movement the height of weeds, the nozzles, and their spacing. of workers and equipment. Successful weed Take care to ensure a uniform spray pattern and, management can be achieved by employing a thereby, a uniform herbicide deposit. Similarly, combination of strategies, which includes the use the speed of travel must be closely regulated. It is of herbicides, to eliminate unwanted vegetation limited not only by safety, but also by the capacity from vineyards. Herbicides, however, act upon of the pump. Regulating the pressure does not suf- different weed species and in different ways; care ficiently alter the output. In general, use speeds of must be taken to ensure that the selected products around 1.5 to 2 miles per hour. will be effective at controlling the weed species that are present in the system. Herbicides are Use low pressures (20 to 35 psi) to ensure coverage also capable of causing serious injury or death of and penetration while minimizing spray drift. vines and/or may have significant unintended NOTE: With glyphosate, reduce the pressure to less consequences on neighboring ecosystems. than 20 pounds (psi). Consequently, applicators must ensure that an acceptable level of crop safety can be achieved Constant agitation of the spray mixture is essen- and that off-site/off-target damage is prevented. tial with wettable powders and dry flowables, and agitation must be vigorous when using oils. The most appropriate choice of herbicide (or com- A defoaming agent can be used. Follow quantity bination of herbicides) will be affected by numerous and directions on label. factors including: • how weed control will be achieved, General Precautions • the kind of weeds to be controlled, 1. Do not apply any herbicide to grapes • the size and/or age of the weeds to be unless there is a label registration for its controlled, use on grapes. • soil type and herbicide incorporation strategy, 2. Check all herbicide or other pesticide uses • the quantity and quality of the spray water, with the processor or field representative • the age and health of the vines. before using. 3. Do not use a combination of herbicides or Application Rate and Equipment other chemicals with herbicides unless the combination has been thoroughly tested and The rate or amount of herbicide to be applied is confirmed to not cause phytotoxic effects. shown as the amount per acre of the actual por- 4. Avoid herbicide application to any part of tion treated (i.e., the area directly under the vine the vine. Do not use weed sprayers to apply row, or the area between vineyard rows), and not other pesticides to vines. the total herbicide to be applied to an acre of vineyard. Thus, a 10-foot row spacing with a 2-foot 5. Do not repeatedly use the same mode of band of herbicide sprayed under the vines would action (MOA) throughout the season (Table 1). be two-tenths (one-fifth) of an acre to be treated or Using different MOAs is part of a good 20% of one acre of vineyard. herbicide resistant management program.

4 Table 1. Mode of action of herbicides registered for use in grapes in the Pacific Northwest. Resistant Weed Herbicide Trade Name1 Chemical Name WSSA Group2 HRAC Code3 Species in PNW?4 Fusilade fluazifop 1 A Yes Poast sethoxydim 1 A Yes Select (and others) clethodim 1 A Yes Matrix (and others) rimsulfuron 2 B Yes Mission flazasulfuron 2 B Yes Kerb pronamide 3 K1 Yes Prowl (and others) pendimethalin 3 K1 Yes Surflan (and others) oryzalin 3 K1 Yes Treflan (and others) trifluralin 3 K1 Yes Princep (and others) simazine 5 C1 Yes Karmex (and others) diuron 7 C2 Yes Roundup (and others) glyphosate 9 G Yes Rely (and others) glufosinate 10 H Yes Solicam norflurazon 12 F1 No Aim carfentrazone-ethyl 14 E No Chateau flumioxazin 14 E No Goal (and others) oxyfluorfen 14 E No Venue pyraflufen-ethyl 14 E No Zeus XC sulfentrazone 14 E No Zeus Prime XC sulfentrazone + 14 E No carfentrazone-ethyl (both) (both) Devrinol napropamide 15 K3 Yes Casoron dichlobenil 20 L No Gallery (and others) isoxaben 21 L No Gramoxone (and others) paraquat 22 D No Alion indaziflam 29 L No 1 Herbicide Trade Names are for example purposes only and does not indicate an endorsement of a specific brand or company. Some active ingredients are available under multiple trade names. 2 WSSA = Weed Science Society of America 3 HRAC = Herbicide Resistance Action Committee 4 At least one weed species resistant to this mode of action documented to occur in ID, OR, or WA; data from Heap, I. The International Survey of Herbicide Resistant Weeds. Available at www.weedscience.org

5 Factors Affecting Control It is possible for weed communities in vineyards to be comprised of species that are naturally sensi- Classification of Herbicides tive to different herbicides or herbicide modes of action. They may also differ with respect to life his- Herbicides differ with respect to how they are used. tory traits or emergence patterns. Herbicide labels When describing herbicides, we can refer to them list the weed species that can be suppressed or as being either ‘pre-emergence’ or ‘post-emergence’ controlled by the active ingredient. The labels will applied. Pre-emergence herbicides are soil-applied also provide instructions on when to time applica- products that act primarily on germinating weed tions to maximize herbicide efficacy and will also seeds or young weed seedlings. They persist in the list appropriate tank-mix partners to help growers environment to provide extended weed control expand the spectrum of weed control. Always read within or across seasons. labels to ensure that herbicide applications will be both effective and safe. Products classified as post-emergence herbicides are applied directly to the foliage of emerged weeds For help on weed identification, visit:http://wine. to elicit control. Post-emergence herbicides can wsu.edu/researchextension/plant-health/weed- be further characterized as being either ‘contact’ management/. In addition, Washington State or ‘systemic’ products. Contact generally refers University Extension also provides a free Weed to herbicides that only affect the tissues that are Identification Service. Information on this service directly treated with the herbicide—these types of can be found at: http://css.wsu.edu/extension/ herbicides do not move (translocate) to untreated weed-identification/. parts of the plant following application. Systemic or translocated herbicides can move from treated The Size and/or Age of the Weed to be plant parts to untreated tissues via the xylem or Controlled phloem. Although some herbicides may exhibit both pre- and post-emergence activity, a combina- Weed control strategies may not always be 100% tion of both foliar and soil-applied products are effective and escapes can occur for numerous typically used to successfully manage weed com- reasons. One of those reasons is the size of plants munities in vineyards. at the time of application. The efficacy of post- emergence herbicides is often diminished when Often, herbicides are referred to as being either products are applied to large/mature plants. This ‘selective’ or ‘non-selective’ (which is synonymous can result from poor spray coverage and the abil- with ‘broad-spectrum’). A selective herbicide is one ity of dense foliage to shield sensitive tissue from that is effective at controlling some species but not herbicide deposition. While plant size is mainly others. Conversely, a non-selective herbicide is an a concern with contact herbicides, the efficacy herbicide that can control many different types of systemic products can also be influenced. For of weedy pests. The most well-known examples example, may perennial species are tolerant of of herbicide selectivity are 1) the abilities of the many herbicides, including translocated products ‘-fops’ and the ‘-dims’ (e.g. fluazifop and clethod- like glyphosate, because their root systems and im) to suppress grasses but not broadleaf species nutrient reserves support regeneration/regrowth. and 2) the control of broadleaved weeds, but not There are several strategies that growers can take grasses, by synthetic auxins (e.g. 2,4-D). to maximize weed control with post-emergence herbicides, including: timing applications to treat Kinds of Weeds to be Controlled weeds while they are small/tender, applying herbicides at appropriate rates and volumes, and using Weed species can be described by the length of label recommended adjuvants to improve herbicide their life cycle. Annual weeds (both winter-and contact and penetration. summer-germinating) emerge, grow, flower, and set seed all within the course of a year. Biennial weeds The development of herbicide resistance is a sig- complete their life cycles over the course of two nificant concern for growers of perennial crops, years whereas perennials can persist across multi- including grapes. Weed species with resistance to ple seasons. Not all herbicides are equally effective glyphosate, glufosinate, and paraquat have been against all three types of weed species. For exam- confirmed in California and Oregon as well as ple, although the seedlings of perennial weeds may other Western states. Incomplete weed control can be controlled by pre-emergence herbicides, much increase the chance of a herbicide resistant biotype like annual species, mature plants are unlikely to reaching reproductive maturity, setting seed, and be impacted. becoming established in a production system. Her-

6 bicide labels will provide instructions to applicators The Quantity and Quality of the Spray Water regarding strategies for resistance management. Additional information can be found at the Weed Water is the main carrier for crop protection Science Society of America’s (WSSA) web-page: products, including herbicides. Consequently, the http://wssa.net/wssa/weed/resistance/. quantity and quality of spray water can impact herbicide distribution and performance. In gen- Soil Type and Herbicide Incorporation Strategy eral, higher carrier volumes have been shown to improve the efficacy of foliar-applied herbicides The length of time that pre-emergence herbicides (glyphosate is a notable exception). Post-emer- may reside in a treated area will be influenced by gence herbicide labels provide instructions regard- multiple factors, such as soil texture and organic ing the recommended application parameters (i.e. matter content. Soils that are high in clay or GPA, pressure, droplet size) to maximize weed organic matter can bind herbicides tightly to the control potential. Carrier volume can also affect soil matrix. Conversely, coarse soils can enhance the delivery of soil-applied products; always read leaching potential. Herbicide persistence is also a the herbicide label to ensure that all herbicides are function of herbicide chemistry. Some herbicides used both effectively and safely. naturally bind very tightly to soil particles whereas others are significantly more mobile. The interac- Water quality factors can also affect herbicide per- tions between soil and herbicide chemistry can formance and safety. For example, herbicides that affect a product’s use rate within a given system. are weak acids (such as glyphosate) can have their This, in turn, may influence how well a herbicide efficacy reduced under alkaline conditions (pH >7). performs, as well as how long it remains in the Salts and soil particles in spray water can bind to treated zone. some herbicides, thereby affecting their dispersal, deposition, and uptake. Water quality recommen- To be effective, pre-emergence herbicides must dations exist for both pre- and post-emergence be incorporated (usually 1–2" deep) into the soil herbicides; read labels carefully. profile. Incorporation is required because these products are mostly active against newly germi- The Age and Health of the Vines nated weed seedlings. Additionally, incorporation is needed to reduce or prevent volatilization and Vine age can affect what herbicides are available photodegradation, which can result in reduced for use in a production system. While competi- herbicide performance. The length of time an tion from weeds is most severe in in newly planted herbicide can remain on the soil surface varies grapes, not all herbicides are labeled for use around dramatically among products. Even if an herbicide young canes. Growers should be aware of re-plants does not require immediate activation to prevent in mature vineyards before making soil-applied product loss, an unincorporated herbicide is unable treatments. Regardless of vine age, residual herbi- to control emerging weeds. While many growers cides should be applied to soil that is settled and will time herbicide applications to take advan- free of cracks to minimize the potential for crop tage of naturally occurring rainfall, uncoopera- injury. Avoid using herbicide-treated soil to backfill tive weather may require the use of irrigation for planting holes. Unless specifically noted on the activation. Some products, due to their mobility label, avoid herbicide spray or mist contact with and potential for crop injury, may be incompatible leaves, green bark, roots, or fruit to reduce the with sprinkler systems; this is of particular concern potential for crop injury. when grapes are grown on shallow, coarse, sandy, or gravelly soils. Crop safety is paramount; however, the safety of species and habitats outside of the treated area are Check pre-emergence herbicide labels carefully also a significant concern. Follow label instruc- to ensure that the product is being applied at tions to reduce the potential of spray or volatil- the proper time of year to effectively target the ity drift and subsequent damage to off-target weed species of concern in a vineyard. Apply and organisms. Surface and groundwater advisories incorporate products as described to prevent crop and buffer zone recommendations are included injury; this includes following timing recommen- on several herbicide labels; read and follow all dations to avoid treating vineyards when and if labeled guidelines to prevent contamination of significant crop damage could occur. aquatic systems.

7 General Precautions planting, preferably in the winter after transplanting. Casoron CS can be applied after vines are 12 1. Do not apply any herbicide to grapes unless months old. there is a label registration for its use on grapes. Diuron (Karmex DF, Diuron 4L) WSSA Group 7: 2. Check all herbicide or other pesticide uses with the processor or field representative photosystem II inhibitor before using. Diuron has pre-emergence and some post-emer- 3. Do not use a combination of herbicides or gence activity. Weeds should not be >2 inches in other chemicals with herbicides unless the height or diameter or else post-emergence control combination has been thoroughly tested and may be compromised. confirmed to not cause phytotoxic effects. Diuron should be applied during the rainy period 4. Avoid herbicide applications to any part of (from about November 1 to February 15 in eastern the vine. Do not use weed sprayers to apply Washington), but not to frozen ground. Spring other pesticides to vines. applications may not be as effective unless rains 5. Do not use the same mode of action (MOA), fall soon after application to incorporate the her- repeatedly, throughout the season. Using bicides; however, heavy rains following a spring different MOAs is part of a good herbicide application may result in plant injury. Application resistant management program. to vineyards under sprinkler irrigation can be hazardous. Apply as a banded application to vineyards that have been established for at least 3 years and Soil-applied Herbicides: that have vines >1.5 inches in diameter. Do not apply to vineyards with shallow, coarse, sandy, or Dichlobenil (Casoron CS, Casoron 4G) WSSA gravelly soils or to soils with less than 1% organic Group 20: inhibits cell wall synthesis matter. Serious herbicide injury to grape roots has occurred when this herbicide is applied under A soil-active herbicide for long-term or seasonal improper conditions. Do not apply more than 5 lbs control of most weeds. Dichlobenil can suppress of Karmex DF per acre in a single use; do not apply the growth of some perennials (Canada thistle, more than 10 lbs per acre per year. Do not apply quackgrass, field bindweed and bermudagrass), more than 4 qts of Diuron 4L per acre in a single although higher use rates are recommended. use; do not apply more than 8 qts per acre per year.

Dichlobenil is most effective when applied in the fall, at the beginning of the rainy season (about Flazasulfuron (Mission) WSSA Group 2: November 1 to February 15 in eastern Washington) acetolactate synthase (ALS) inhibitor and when the ground is cool. Application before Mission is labeled for the control of certain broad- a rain will reduce volatility and improve weed leaf and grass weeds including annual ryegrass, suppression. Do not apply when the ground is common mallow, clover and willowherb. Mission frozen. Applications can be made in the spring up has both pre- and early post-emergence activity; to about May 1 (when the soil surface is still 60°F weeds should be <4 inches tall and grasses should or below). If an application is not followed closely not be tillering in order to maximize post-emer- by rain, either incorporate into the soil surface gence control potential. If weed emergence is sub- mechanically or use a light sprinkler irrigation (0.5 stantial at the time of application, consider mixing to 1 inch of water); do not overwater to the point flazasulfuron with an approved post-emergence of runoff. This chemical can be used in sprinkler- herbicide to improve control. irrigated vineyards but injury can occur; use the lower rate of chemical and reduce the amount of Apply pre-emergence as a directed spray to the soil water applied in the first irrigation to 0.5 to 1 inch under vines that have been established for at least of water. Consult agricultural authorities before 3 years; protective sleeves (nonporous wraps, grow applying dichlobenil to sprinkler-irrigated vine- tubes, waxed containers) are required for third yards. Avoid use on coarse, sandy, gravelly, or shal- year vines. Do not apply where grapevine roots are low soils because of potential injury. Do not apply exposed or to gravelly soils. Must be activated with to recently cultivated or loose soil or when the soil rainfall or irrigation of 0.25 to 0.5 inch for pre- surface is wet and warm (above about 70°F); delay emergence control; pre-emergence efficacy will be application until the soil is settled and dry. Do not maximized if the product is applied to bare soil. Do apply to young vines until four weeks after trans- not apply more than two applications of 2.85 oz of

8 formulated product per acre per year (maximum of Alion is most effective when applied in the fall or 0.089 lbs of active ingredient or 5.7 oz of Mission early spring to dry soil surface that does not have per acre per year). The minimum allowed interval crack or depressions. Apply as a uniform broadcast between treatments is 3 months. Do not apply or banded application. Alion applications should within 75 days of harvest. A 25-foot buffer must be followed by 48 hours without irrigation or be maintained between the point of direct applica- rain; activating moisture (0.25 to 0.5 inches) must tion and the closest downwind edge of sensitive be received within 21 days or before weed seeds terrestrial habitats (forested areas, riparian areas), germinate. Do not use on sand or soils contain- freshwater habitats (lakes, rivers, sloughs), and ing >20% gravel. Alion should not be applied to estuarine/marine habitats. frozen or snow covered soils, or saturated soils. Use only on vines established at least three years Flumioxazin (Chateau SW) WSSA Group 14: that are exhibiting normal growth and good vigor. protoporphyrinogen oxidase (PPO) inhibitor Ensure that there is 6 inches of soil between the soil surface and the major portion of the root. Do Chateau has both pre- and early post-emergence not apply more than 5 fluid ounces of formulated activity and can control broadleaf weeds up to product (0.065 lbs of active ingredient) per acre per about 2 inches tall. If weed emergence is significant year; coarse soils with less than 1% organic matter or weeds are large, consider mixing flumioxazin require a lower use rate per application. If making with an approved post-emergence herbicide to more than one treatment per year, allow for 90 improve control. days between applications. Do not apply within 14 days of harvest. Clean spray tank thoroughly The preferred time for pre-emergence applications after use. Surface and groundwater advisories are is fall, in order to maximize the potential for rain included on the label because of potential to harm to activate the herbicide. Do not apply to vines nontarget aquatic organisms, and potential for established less than 2 years, unless they are trel- runoff and percolation to ground water. lised at least 3 ft from the ground, and protected by nonporous wraps, grow tubes, or waxed con- Isoxaben (Gallery DF, Trellis SC) WSSA Group tainers. Do not apply to non-trellised vines unless 21: cell wall synthesis inhibitor they are free-standing. New plantings of own-rooted varieties should have root systems a minimum A pre-emergence applied herbicide for the control of 8 inches below the soil surface. Chateau should of many annual broadleaf weeds. not be applied to soils that are susceptible to dispersal by wind; wind-blown, herbicide-treated soil Available for non-bearing (Gallery) and bearing can cause serious injury to grapes and other plants. (Trellis) vineyards, but do not apply to newly Do not apply after budbreak through final harvest transplanted vines until the soil has settled and is in juice and wine grapes, unless using shielded free of cracks. Do not apply Trellis within 165 days application equipment and applicator can ensure of harvest. Must be incorporated within 21 days spray drift will not come in contact with crop fruit and before weeds emerge. Activate with 0.5 inch of or foliage. Dust created by mowing can also injure water or shallow cultivation before weeds emerge. sensitive species; do not mow between budbreak Most effective when applied to soil that is debris and final harvest. The application and maximum free. For bearing vineyards, do not make more than use rates can vary with weed species and soil type, 2 applications per year up to a max use rate of 1 lb but will not exceed 12 oz of formulated product of active ingredient per acre per year. Select appli- per acre per application and 24 oz of formulated cation rates based on weeds present. product per acre per year. Do not apply within 60 days of harvest. Do not apply within 300 yards of Napropamide (Devrinol 2-XT, 50 DF) WSSA non-dormant pears. Group 15: inhibits very long chain fatty acid synthesis Indaziflam (Alion) WSSA Group 29: inhibits cellulose biosynthesis A pre-emergence herbicide for the control of some annual grasses and broadleaf weeds. Will not give Alion is labeled for the pre-emergence control of complete control of nightshade, flixweed, tansy many annual grasses and broadleaf weeds. Con- mustard, tumble mustard, or perennial weeds. trols perennial weeds from seed, only. The spectrum of weeds controlled will be affected by rate Apply fall through spring before weeds germinate. and the timing of activation. May be applied to both newly planted and estab-

9 lished vineyards. Applications made from Novem- essary to activate this herbicide. If weeds begin to ber 1 to February 15 should be incorporated with emerge before herbicide incorporation, a shallow irrigation or shallow cultivation if rainfall does not cultivation (1 to 2 inches) will kill existing weeds occur within 2 weeks of treatment. Performance is and place the herbicide in the zone of weed seed reduced if excessive residue occurs on the soil sur- germination. Surflan rates vary between 2 and 6 qt face. Applications made during the spring should per acre per application depending on the desired be activated with sufficient water to wet the soil length of weed control; the maximum use rate is to a depth of 2 to 4 inches within 24 hours. Can 12 lbs of active ingredient per acre per year. The be used safely in sprinkler-irrigated vineyards. The interval required between repeat applications is pre-harvest interval is 35 for the DF formulation 2.5 months. and 70 days for 2-XT. Do not apply more than 4 lbs of active ingredient per acre per crop cycle. Oxyfluorfen (Goal 2XL, Galigan 2E, GoalTender) WSSA Group 14: proto- Norflurazon (Solicam DF) WSSA Group 12: porphyrinogen oxidase (PPO) inhibitor inhibits carotenoid biosynthesis Provides both pre-emergent and early post- A broad spectrum pre-emergence herbicide that emergent control of broadleaf weeds in dormant will control many annual broadleaf and grass grapes. It is most effective post-emergence when weeds found in vineyards. Solicam does not have the seedling weeds have less than four leaves. Post- any post-emergence weed control activity. emergence weed control can be improved by tank- mixing with appropriate partners and adjuvants. Solicam can be applied from fall to early spring before the weeds emerge to non-frozen soil. The Direct the spray toward the base of vines in late soil should be settled and firm at the time of winter or spring, avoiding direct plant contact; application and the surface must be free of soil apply to bare soil. Apply after harvest, but before clods, depressions, weeds and other plant residue. bud-swell in spring. The closer grapes are to bud Requires rain to activate. If no rainfall occurs swell at time of application, the greater the chance within 4 weeks after application, the product of crop injury. Do not apply to grapes established must be activated by sprinkler irrigation. Applica- less than 3 years unless they have been staked or tion to vineyards under sprinkler irrigation may trellised 3 feet above the ground. Do not apply be hazardous to vines growing on coarse soils; do to grapes that are not staked or trellised unless not use on wine grapes grown in gravelly, sandy, they are free-standing. Apply only to healthy loamy sand, or sandy loam soils in Washington. vines. Overhead moisture within 3 to 4 weeks will Norflurazon should not be applied to vines estab- enhance herbicidal activity. The maximum use rate lished less than 2 years. Whitening may occur if is 2.0 pounds active ingredient per acre per season. norflurazon is applied within 3 months after bud The lower rate is for control of susceptible broadleaf break. The maximum use rate per year for grapes seedling weeds; the higher rate should be used for should not exceed 5 lbs of formulated product larger weeds or for preemergence control. per acre per year. Do not apply within 60 days of harvest. Pendimethalin (Prowl H2O, Prowl 3.3 EC) WSSA Group 3: microtubule assembly Oryzalin (Surflan AS, other tradenames) WSSA inhibitor Group 3: microtubule assembly inhibitor Prowl H2O and Prowl 3.3 EC are pre-emergence Surflan is a pre-emergence herbicide that is par- herbicides that are particularly effective against ticularly effective against annual grasses and some grasses. broadleaved weed species but will not give complete control of nightshade, tansy mustard, or Apply directly to the ground in dormant grapes tumble mustard. before bud-break and before weeds emerge. Overhead moisture is required within 7 days Can be used in newly planted (if the soil has for herbicide activation. Do not apply to newly settled around vines) and established vineyards. transplanted vines until the soil has settled and no Apply in late fall or early spring. Safe to use under cracks are present. If applying before transplanting, sprinkler irrigation. Treated areas must be free of do not allow treated soil to come into contact established weeds and well worked prior to spray with roots. Do not apply during or after bud swell application. A half-inch of rain or irrigation is nec- in the spring. Do not apply over the tops of vines

10 with leaves or open buds. Both labels include Simazine (Princep 4L, Princep Caliber) WSSA specific instructions regarding pre-plant or surface Group 5: photosystem II inhibitor incorporated, surface-applied, and pre-emergence applications. The use rate is determined by the Princep is a soil applied herbicide with efficacy weeds requiring control and the length of control against some grasses and broadleaf wed species. needed. The pre-harvest interval for Prowl H2O is 90 days. Prowl 3.3 EC is not labeled for use in Apply during the rainy period (from about Novem- bearing vineyards. ber 1 to February 15 in eastern Washington) as a single application. Do not apply to frozen ground. Requires surface moisture for activation. Do not Pronamide (Kerb 50-W, Kerb SC) WSSA apply to vineyards established less than 3 years or Group 3: microtubule assembly inhibitor to vineyards with shallow, coarse, sandy, or gravelly soils. Serious herbicide injury to grape roots has Pronamide is a soil-applied product that is used for occurred when applied under improper conditions. the control of grasses (annuals and some peren- Application to vineyards under sprinkler irriga- nials) and some broadleaved species primarily for tion is hazardous. Do not apply more than 4 lbs pre-emergence although Kerb can control some of simazine (active ingredient) per acre per year. small weeds that have emerged.

Apply only once in the fall or early winter as a Sulfentrazone (Zeus XC, Zeus Prime XC) directed application when the soil temperature WSSA Group 14: protoporphyrinogen oxidase is below 55°F, but not when soil is frozen. Kerb is (PPO) inhibitor most effective when applied prior to weed emergence, to soil that is relatively free of residue, and A pre-emergence or early post-emergence herbicide when the application is followed by rainfall or for controlling several species of annual broadleaf weeds. If weeds are emerged, mix sulfentrazone irrigation. Use rate will be determined by the weed with an approved post-emergence herbicide. species to be controlled and soil type although the maximum use rate per acre per year is 4 lbs of Apply as a uniform broadcast soil application to active ingredient. Do not use on vines less than vineyard floors or as a uniform band directed at 1 year old, on fall-transplanted stock that has been the base of the vines then incorporate into the soil transplanted less than 1 year, or to spring-trans- with rainfall or irrigation. Trunks can be wrapped planted stock that has been transplanted less than in non-porous wraps, grow tubes, or wax container 6 months. Pronamide is a restricted-use chemical. to protect against spray contact. Do not apply to vines younger than 3 years old. Activity of sulfen- Rimsulfuron (Matrix FNV, Matrix SG) WSSA trazone increases dramatically under alkaline soil Group 2: acetolactate synthase (ALS) inhibitor conditions or when irrigated with alkaline water. The pH of the spray solution should be between 5 Matrix has both pre-emergence and very early and 9. If applied after bloom, use a shielded sprayer post-emergence activity. When weeds are present at to avoid movement of spray mist to flowers. application, include a labeled burndown herbicide. Sulfentrazone should not be applied to soils that are susceptible to dispersal by wind. Do not apply Can be applied broadcast to vineyard floor or to frozen soils. Do not apply more than 12 oz of banded at the base of the vines. Best pre-emergence Zeus XC per broadcast acre per 12-month period. results are obtained when the soil is debris-free and A prepackaged mix with carfentrazone-ethyl (Zeus moist at time of application, and the site receives Prime XC) is also available for grapes established 0.5 inches of rain or irrigation moisture within 2 at least 2 years. Do not apply more than 15.2 fluid weeks of application. Crops must be established for ounces of Zeus Prime per acre per year. Do not 1 year before application (vines should be healthy apply within 3 days of harvest. and growing vigorously). Susceptible weeds are controlled from 60 to 90 days after application. Trifluralin (Treflan 4D, Treflan 4EC, Treflan Two applications separated by 30 days are allowed HFP) WSSA Group 3: microtubule assembly if applied in bands that cover half of the vineyard. inhibitor Do not exceed 4 ounces of formulated product per acre on a broadcast basis per year. For best results, A soil-applied product that is used for the control maintain spray tank solution at pH 5 to 7. The pre- of grasses (annuals and some perennials) and many harvest interval is 14 days. broadleaved species.

11 Can be used prior to transplanting as well as estab- Fluazifop and sethoxydim are registered for use in lished vineyards. Apply before times of expected nonbearing and bearing vineyards; clethodim is weed emergence or immediately after existing registered for use only in nonbearing vineyards that weeds are controlled. Trifluralin is best applied in will not be harvested within 1 year after treatment. the spring to provide almost season-long control They are foliage applied, translocated herbicides of weeds. Must be mechanically incorporated 1 to which will control most actively growing grass 2 inches deep within 24 hrs following application weeds. The herbicide will not control annual blue- to be effective and prevent loss of activity. Mixing grass or the fine-leaf fescues. Results can be erratic activities should be done by equipment that will on grasses stressed from lack of vigor, drought, high not injure vine roots. Since trifluralin (Treflan) is temperature, or low fertility. Apply fluazifop to not leached into the soil, it is best applied in the actively growing grasses as a directed spray in water. spring and can be used in vineyards with sandy Add 1 quart crop oil concentrate or 0.5 pint nonion- soils or sprinkler irrigation. Use lower rates on ic surfactant to 25 gallons of spray material. Apply sandy soils or soil containing low organic mat- when susceptible grasses are in the labeled growth ter levels. Lower rates should also be used in areas stage. Apply clethodim to actively growing grasses receiving less than 20 inches rainfall and irrigation. as a directed spray in water. Add 1 pint of nonionic See label about mist propagated vines. The pre- surfactant to 50 gallons of spray material. Apply harvest interval is 60 days. sethoxydim to actively growing grasses listed on the label at the 4- to 5-leaf stage (6 to 12 inches tall). Add 2 pints of a non-phytotoxic oil concentrate per Foliar-applied Herbicides: acre. Do not apply to grasses which are stressed. Carfentrazone-ethyl (Aim EC) WSSA Group 14: protoporphyrinogen oxidase (PPO) inhibitor Glufosinate (Rely 280) WSSA Group 10: glutamine synthase inhibitor A contact herbicide that is active on annual broadleaf weeds. Foliage applied, contact herbicide used to control annual broadleaf and grass weeds and to suppress Carfentrazone-ethyl may be applied alone or as perennial weeds. a tank mixture with other labeled herbicides as a post-emergence directed treatment or as a hooded Apply when weeds are small and actively growing. spray between rows to control emerged and Use as a directed spray. Avoid contact of spray or actively growing weeds. Good spray coverage of mist on new foliage or green shoots as severe vine the weeds is essential for control. May be applied injury may result. Use directed spray and shield anytime during the season. Control is enhanced young vines. Thorough coverage of target weeds with the addition of a nonionic surfactant or is essential for control. No additional surfactant is crop oil concentrate. Care must be taken not to needed. May be tank mixed with labeled residual allow spray mist to contact desirable fruit, foliage herbicides to control later germinating weeds. or green stem tissue. Lower rates may be used to Apply in a minimum of 20 gallons of water per control small susceptible broadleaf seedling weeds acre. Do not exceed 4.5 lb ai/acre per 12-month at the 2- to 3-leaf stage. The higher rate is needed season. Apply only to grapevines established at to control larger weeds up to the 6-leaf stage. Do least 1 year. Do not apply within 14 days of harvest. not use on newly-transplanted vineyards. Do not apply more than 2 oz of formulated product per Glyphosate (Roundup and other tradenames) acre per application. Do not apply more than WSSA Group 9: inhibits EPSP synthase 7.9 oz of formulated product per acre per season. Do not make sequential applications less than A translocated herbicide which controls many 14 days apart. The pre-harvest interval is 3 days. annual and perennial weeds, both grasses and broadleaves.

Fluazifop (Fusilade DX), clethodim (Select and For optimum control of perennial weeds such as other tradenames) and sethoxydim (Poast) Canada thistle, field bindweed, and quackgrass, WSSA Group 1: acetyl CoA carboxylase consult labels for recommended rates and correct (ACCase) inhibitors timing in relation to weed growth. Adding surfactant or mixing ammonium sulfate according Post-emergence control of annual and perennial to label may improve control of slightly stressed grasses. weeds. Apply in 20 to 60 gallons of water per acre

12 on emerged and actively growing weeds. Glypho- of water for thorough coverage of the weeds. Five sate does not provide residual weed control. If applications are allowed per year. This is a restrict- repeated treatments are necessary for weed con- ed-use herbicide. Do not ingest or inhale spray trol, do not exceed a total of 8 lbs ae per acre per mist. Wear protective clothing, face shields when year. Do not treat between 14 days before harvest mixing, and respirators during application. to fall dormancy when green foliage or shoots are in the spray zone. Follow all precautions on label. Pyraflufen-ethyl (Venue) WSSA Group 14: Repeated glyphosate applications have selected for protoporphyrinogen oxidase (PPO) inhibitor resistant biotypes of ryegrass, as well as other weed species, in the PNW. To avoid weed resistance, A contact herbicide that is active on annual broad- rotate and mix weed control practices. leaf weeds.

Paraquat (Gramoxone SL 2.0, Firestorm) WSSA Apply when the weeds are less than 4 inches tall Group 22: photosystem I electron diverter or 3 inches across. Use as a directed spray and thoroughly cover weeds. Use lower rates for small Foliage applied, contact herbicide used to control weeds and higher rate for larger weeds. Avoid annual broadleaf and grass weeds and to suppress contact with desirable foliage, green bark, or fruit. perennial weeds. Use an approved agricultural buffering agent if using in water of equal to or greater than pH 7.5. Apply as a directed, shielded spray to the base of The addition of crop oil concentrate or nonionic vines when grasses and other weeds are growing surfactant is recommended for optimum control. actively and new growth is from 1 to 6 inches Tank mixing can increase the weed spectrum that high. With mustard-type annual weeds, apply is controlled. Mix only the amount of solution before leaves exceed 1 inch in diameter. Avoid that can be sprayed within 4 hours. Do not make contact of spray or mist on new foliage or green more than 3 applications or exceed 6.8 fluid shoots as severe vine injury may result. Add a non- ounces per acre per season. Allow at least 30 days ionic surfactant or crop oil concentrate according between applications. Shield 1 year old or younger to label; avoid anionic formulations that react in vines with non-porous wraps, grow tubes, or wax the tank to form insoluble precipitates. Paraquat is containers. Apply in a minimum of 20 gallons of corrosive to aluminum. Spray in 50 to 200 gallons water per acre.

13 HERBICIDE INJURY

Herbicide Injury Northwest Vineyards (PNW 644) for pictorial guides to determining damage caused by various herbicides. Herbicide injury symptoms can sometimes be confused with injury resulting from viruses or deficien- Report incidences of injury or severe symptoms in cy of plant nutrients. 2,4-D, glyphosate, and some grapes from herbicide drift to the Washington State other classes of herbicides affect the new growth Department of Agriculture toll-free 1-877-301-4555. of grapevines, causing deformation of both shoots and leaves. The symptoms tend to disappear later in the season as the malformed foliage is covered 2,4-D Drift Documentation up by new growth. Serious crop damage can result if contamination occurs during the early portion To report damage in vineyards due to 2,4-D drift, of the growing season. Leaf symptoms of herbicide adequate documentation is necessary. Most docu- injury and other disorders can be found online at mentation must occur early in the spring, and WSU (http://wine.wsu.edu/extension/). See the weekly notes on plant development and the devel- Field Guide for Integrated Pest Management in Pacific opment of damage symptoms are also needed.

14 WEED MANAGEMENT PROGRAM FOR GRAPEVINES

Broad categories of weeds and vineyard age are described for each herbicide. Detailed application notes are found in the previous sections on “Soil-applied” and “Foliar-applied” herbicides. It is important to reference those sections and the label before any application.

MATERIAL PER ACRE TREATED* Rate of formulated Weeds to be Active ingredient product per application controlled and formulation per treated acre Vineyard age

PRE-EMERGENCE WEED CONTROL

Annual & some dichlobenil (a: Casoron 4G, a: 100–150 pounds Casoron 4G for vineyards which have been transplanted perennial weeds b: Casoron SC) more than 4 weeks; Casoron SC after vines have been b: 1.4–2.8 gallons transplanted for at least 12 months. Annual grasses & indaziflam (Alion) 3.5–5.0 fluid ounces Use only on vines established at least three years that are broadleaf weeds exhibiting normal growth and good vigor.

Annual broadleaf isoxaben (a: Gallery DF, a: 0.66–1.0 pounds Gallery is labeled for non-bearing crops, only. Trellis is weeds b: Trellis SC) available for non-bearing and bearing vineyards, but do b: 20.3–31 fluid ounces not apply to newly transplanted vines until the soil has settled and is free of cracks.

Annual grasses & napropamide a: 2 gallons For newly planted and established vineyards. broadleaf weeds (a: Devrinol 2-XT, b: Devrinol 50 DF) b: 8.0 pounds

Annual grasses & norflurazon (Solicam DF) 1.25–5.0 pounds Norflurazon should not be applied to vines established broadleaf weeds less than 2 years. Annual grasses, some oryzalin (Surflan AS) 2.0–6.0 quarts Can be used in newly planted (if the soil has settled around broadleaf weeds vines) and established vineyards. Annual grasses, some pendimethalin a: 2.4–4.8 quarts Prowl 3.3 is labeled only for nonbearing vineyards; Prowl broadleaf weeds (a: Prowl 3.3 EC, H2O may be used in nonbearing or bearing vineyards. b: Prowl H2O) b: 3.2–6.3 quarts Do not apply to newly transplanted vines until the soil has settled and no cracks are present. Annual grasses, some pronamide a: 2.0–8.0 pounds Do not use on vines less than 1 year old, on fall- broadleaf weeds, (a: Kerb 50W, transplanted stock that has been transplanted less than some perennials b: Kerb SC) b: 2.5–9.5 pints 1 year, or to spring-transplanted stock that has been transplanted less than 6 months. Annual grasses & simazine a: 2.0 quarts For vineyards established at least 3 years. broadleaf weeds (a: Princep 4L, b: Princep Caliber 90) b: 2.2 pounds

Annual grasses, some trifluralin (a: Treflan 4D, a, b, c: 2.0-4.0 pints For newly planted and established vineyards. For newly broadleaf weeds b: Treflan 4 EC, c: Treflan HFP) planted vineyards, follow rate on label based on soil type.

PRE-EMERGENCE AND EARLY POST-EMERGENCE WEED CONTROL Annual grasses & diuron (Diuron 4L) E WA 0.8-2.4 quarts For vineyards established at least 3 years. broadleaf weeds W WA 1.6–2.4 quarts

Annual grasses & flazasulfuron (Mission) 2.14–2.85 ounces For vineyards established at least 3 years; nonporous broadleaf weeds wraps, grow tubes, waxed containers, or other protective sleeves are required for vines in their 3rd season of growth. Annual broadleaf flumioxazin (Chateau) 6.0–12.0 ounces For vineyards established at least 2 years. weeds

*Rates as given are per acre of ground sprayed. For band or spot treatment, calculate rates according to the actual portion of an acre treated.

15 WEED MANAGEMENT PROGRAM FOR GRAPEVINES MATERIAL PER ACRE TREATED* Rate of formulated Weeds to be Active ingredient product per application controlled and formulation per treated acre Vineyard age PRE-EMERGENCE AND EARLY POST-EMERGENCE WEED CONTROL (continued) Annual grasses & oxyfluorfen a: 5.0–8.0 pints for pre- For vineyards established at least 3 years. broadleaf weeds (a: Goal 2XL, emergence; 2.0–8.0 pints b: GoalTender) for post-emergence

b: 2.5–4.0 pints for pre- emergence; 1.0–4.0 pints for post-emergence

Annual grasses & rimsulfuron a, b: 4.0 ounces Crops must be established for 1 year before application broadleaf weeds, (a: Matrix FNV, (vines should be healthy and growing vigorously). some perennials b: Matrix SG)

Annual broadleaf sulfentrazone a: 8.0–12.0 fluid ounces For vineyards established at least 3 years. Zeus Prime XC Weeds (a: Zeus XC, (a pre-mix with carfentrazone-ethyl) is available for grapes b: Zeus Prime XC) b: 7.7–15.2 ounces established at least 2 years. POST-EMERGENCE WEED CONTROL Annual broadleaf carfentrazone-ethyl (Aim EC) 1.0–2.0 fluid ounces Do not use in newly-transplanted vineyards. weeds Annual & perennial fluazifop (Fusilade DX) 6–24 fluid ounces Labeled for use in bearing and non-bearing vineyards. grass weeds Annual grasses & glufosinate (Rely 280) 1.5–2.56 quarts Do not apply to vines established less than 1 year unless broadleaf weeds, protected by non-porous wraps, grow tubes, or waxed top kill of perennial containers. grasses Annual & perennial glyphosate (Roundup, 14 fluid ounces–1.78 quarts Use as a directed spray in established vineyards or for site weed control many others) preparation before transplanting new vines Annual grasses & paraquat a: 2.5–4.0 pints broadleaf weeds, (a: Gramoxone SL 2.0, top kill of perennial b: Firestorm) b: 1.7–2.7 pints grasses Annual broadleaf pyraflufen-ethyl (Venue) 1.0–4.0 fluid ounces Do not apply to vines established less than 1 year unless weeds protected by non-porous wraps, grow tubes, or waxed containers. Annual & perennial sethoxydim (Poast) 1.5–2.5 pints Labeled for use in bearing and non-bearing vineyards. grass weeds Annual & perennial clethodim (a: Select 2 EC, a: 6–8 fluid ounces Labeled for use in non-bearing vineyards only. grass weeds b: Select Max) b: 9–16 fluid ounces

*Rates as given are per acre of ground sprayed. For band or spot treatment, calculate rates according to the actual portion of an acre treated.

16 PESTS OF GRAPEVINES

Black Vine Weevil Because BMSB populations are known to gradu- ally build over several years before becoming an This pest has decreased in importance as producers economic pest, the current focus in Washington have switched to drip irrigation systems. Black vineyards is detection. There are many native vine weevil generally overwinters in the immature, stink bugs that look similar to BMSB, yet the larval or grub stage. The young larvae feed on combination of these three key characteristics can small roots and root hairs. Larger larvae feed on distinguish BMSB: 1) light and dark bands on the larger roots, quite often within a few inches of the antennae, 2) smooth “shoulders” with no spikes, crown. The larvae change to inactive pupae and and 3) dark and light bands around the abdomi- remain in earthen cells 3 to 4 inches below the nal margins. Pictures and additional descriptions ground in mid-April. The first adults emerge about of each life stage can be found in the Field Guide May 20, and emergence peaks about June 20. for Integrated Pest Management in Pacific Northwest All black vine weevils are females; males are not Vineyards (PNW644) or http://www.stopbmsb.org. known. Each weevil is capable of laying 300 to 500 If you detect BMSB in your vineyard, please con- eggs. The first eggs are laid about 3 weeks after tact your local extension office or research center. the adults emerge. Therefore, a grower has about 3 weeks from the time the first weevils emerge Cutworms until controls must be applied. Cutworms are the larvae, or wormlike stage, of The adult is a black-snouted beetle approximately night-flying gray to brown moths. Several species 1/2 inch long (12.7 mm), having small gold patch- or kinds of cutworms cause injury in vineyards. es on the fused wing covers. The beetle cannot fly. Adult beetles feed on grape clusters during June Cutworms and related species usually overwinter and July. Damage consists of girdled berry stems or as partially grown (2nd or 3rd instar) cutworms cluster stems. Severely injured clusters have berries in the soil, or under debris in the vineyard. Young that do not size or ripen properly. Occasionally ber- cutworms begin feeding on winter annual weeds, ries or parts of clusters are chewed off. Weevils are particularly mustards, during warm periods in active and do most of their damage at night. They February and March. By the time of bud break they return to the ground at daylight to hide under are nearly full grown. They remain under cover clumps of soil, debris, or loose bark at the base of (within cracks in soil or plant debris, or under the plant. Therefore a weevil population may go rough bark on trunk) during the day, but climb the undetected for a long time. vines to feed on buds or shoots at night—or on cloudy days when light levels are low. Registered synthetic pyrethroid insecticides can be applied as rescue treatments if infestations are Euxoa spp. cutworm types overwinter as eggs which severe. Direct insecticide sprays at the crown (base hatch about April 10. Young larvae may climb vines of the vine) and up several feet from the soil sur- and feed on buds or shoots. Some years cutworm face. Pyrethroid insecticides are biologically disrup- injury can begin in late March or early April (spotted tive and can cause populations of secondary pests, cutworm) and continue through May into early June including spider mites, to flare. (redback cutworm). Damage to newly planted vines may mean loss of shoot growth (nothing to train) or death of the plant; damage to older vines may cause Brown Marmorated Stink Bug fruit production losses. Cutworm damage is often intensified by discing the cover crop in early May. In the eastern United States, Brown Marmorated Stink Bug (BMSB) is an invasive insect that has had Managing cutworms severe economic impacts on numerous commodi- ties. BMSB was discovered in the Pacific Northwest Sampling for spotted cutworms before or at the several years ago. It has not yet been a problem time of bud break is very difficult. Therefore, grow- in commercial vineyards because the population ers may wish to make prophylactic applications of sizes remain relatively low in eastern Washington. pyrethroid barrier sprays targeted towards the base Western Washington has higher populations, yet of the trunk for cutworm control based on one of no vineyards have reported infestations. the following criteria:

17 l. Since early season cutworms are difficult to Drosophila suzukii find and injuries caused by 2nd or 3rd instars are small, the decision to spray may be D. suzukii, also known by the unofficial common based on the recent history of the vineyard. name of spotted wing drosophila (SWD), invaded Usually, cutworm problems in established all Washington State grape producing counties in vineyards occur in the same portions of a 2010. It is a fruit fly, but unlike other common and vineyard each year. In those cases, a prophy- ubiquitous fruit flies, SWD has a serrated oviposi- lactic application of a synthetic pyrethroid as tor used to puncture undamaged fruit and lay eggs. barrier may be warranted. We have direct observation of it infesting ripening cherry, raspberry, blueberry, and apricot; it has 2. Inspect vineyards carefully for presence of also been observed attacking other soft-flesh fruit cutworms. Injured buds may be an indication such as nectarines, peaches, and volunteer fruits of spotted cutworm injury (late March–early including blackberry and hawthorn. So far, grapes April). Injured buds and new shoots may be in Washington have been unaffected by D. suzukii, caused by large spotted cutworms (mid-to therefore, there are no recommendations for con- late April) or redback cutworms (late April to trolling D. suzukii. early June). Apply sprays when bud injury reaches 5% to 10% of the total bud crop. Populations or prevalence of D. suzukii or SWD Base sprays for shoot or cluster bud injury is greatly influenced by temperature. In Eastern on the amount of injury and economics. Washington, populations have generally remained lower in the early and mid season when tempera- 3. Newly planted vines need special protection. tures are exceeding 90°F, yet populations rise later Frequently the disturbance of weeds or other in the season when daytime temperatures are cover in the planting process leaves little cooler. In Western Washington, where tempera- food for resident cutworms. Since there may tures can be more moderate, populations can build only be a few buds on a young plant, injury through the season. This is a problem for many by cutworms may be severe. In this case, berry growers, but again, this pest does not appear chlorpyrifos may be used. to affect undamaged grapes and does not warrant Registered synthetic pyrethroid insecticides specific control. can be applied as rescue treatments if infestations are severe. Pyrethroid insecticides are biologically disruptive and can cause popu- Grape Flea Beetle lations of secondary pests, including spider The grape flea beetle,Altica chalybea, is mites, to flare. occasionally a serious pest of grapes in the Midwestern U.S. It is rarely a pest in the PNW but How to use insecticides for cutworms populations can develop that defoliate newly- planted, non-bearing vineyards in mid to late Follow label instructions. A synthetic pyrethroid spring, especially when grow tubes are used on barrier should be sprayed at sufficient concentra- young vines. Grape flea beetles are shiny metallic tions and directed in sufficient volume of water blue and about 3/16 inch (4.8 mm) long. They to cover the trunk of the vine from just above the have long antennae and swollen “thighs” (i.e., soil surface to a height of between 16 and 18 femora) on their last pair of legs. When the inches. Red-eye sensors that control spray volume adults are disturbed they jump; hence the name and discharge a targeted spray at only the base of flea beetle. The larvae are extremely cryptic and trunks and vineyard posts are the most efficient typically not observed. The adults are highly method of applying the barrier sprays. Research clustered in their distribution within a vineyard has demonstrated that barrier sprays are most and can be observed in substantial abundance. effective if they are applied during the first two weeks of March. Larvae and adults feed on the upper and lower leaf surfaces producing a skeletonized or lacey appear- Registration limitations of the more effective ance, although this injury is usually not serious. materials complicate control. Begin control in the The most serious damage occurs in the spring as delayed-dormant (wooly bud) period, just before the larva emerge from overwintering sites and feed buds start to swell. If the treatment is for cutworms on newly swollen grape buds. The adult beetles alone, direct spray to the trunks, wire, and posts chew holes in the sides and ends of the buds often leading from the ground to the cordons. hollowing out the whole bud only leaving the

18 overwintering scleritized bud sheath. Their feeding tion of several chemigations or foliar applications damages primary and occasionally secondary and of insecticides are sufficient for managing mealy- tertiary buds and can be confused with cutworm bug infestations. Research has documented that damage. However, cutworm damage tends to be managing mealybugs does slow the spread of grape more apparent and occurs on multiple swelling leafroll disease, however, increased insecticide buds on an individual vine. Flea beetle damage to applications in an attempt to eradicate mealybugs buds in mature vineyards is more sporadic than has not substantially slowed the spread of grape cutworm damage and less severe after buds have leafroll disease in vineyards. Disease severity and grown to 1/2 inch (12.7 cm) or more. Young plants expression of GLRD symptoms varies among virus can sustain more damage even through mid-summer. strains, grape varieties and climatic conditions. However, there is no cure treatment for GLRD Monitoring for flea beetle should be done in and infested vineyards will produce lower yields conjunction with cutworm monitoring. Because and juice quality. A secondary contamination can of the similarities in feeding, the cutworm proto- occur in late-season vineyards when the honeydew col should detect populations of grape flea beetle excreted by mealybugs drips on the foliage, twigs, adults and their damage. and fruit. Sooty mold, a black fungus, may grow on this honeydew, producing a sooty appearance. Control is most important in newly-established Serious contamination can destroy the market vineyards and typically not recommended on value of the crop for processing. mature vines. Insecticides will reduce adult populations. Vineyards infested with flea beetle Adult grape mealybugs are about 1/4 inch populations the prior season should be monitored (6.35 mm) long, pink to dark purple, and covered rigorously in spring to control the larvae. Cur- with a white waxy powder. Strands of the wax ex- rent recommendations are to apply insecticides tend from the body. Eggs are yellow to orange and for larvae if more than 4% of buds are damaged in are laid in cottony egg sacs. Crawlers are tiny, 1/16 young vineyards. There are numerous insecticides to 1/8 inch (1.25–3.1 mm) long, pink to tan, and registered for the control of flea beetles on grapes. quite active. Some of the active ingredients that are effective are spinosad, spinetoram, chlorantraniliprole, Mealybugs overwinter as eggs or crawlers in the egg imidacloprid, thiamethoxam, and acetamiprid. sacs, usually in the bark cracks or under the bark scales on the trunk and in the arms or cordons. In the spring, crawlers move quickly to new growth to Grape Leaffolder feed. They mature in June, and adults move back to older wood to lay eggs. A second generation of Grape leaffolder has made a recent resurgence in crawlers will move to new growth, including the very isolated locations in eastern Washington. fruit, where they mature through July and August. Damage from leaffolder activity after fruit set is The honeydew produced by this generation may rarely a concern; in California, 20% damage has contaminate fruit. been observed without damage to fruit quality or ripening. Damage to yields may occur if severe Control procedures are most effective when the leaffolding occurs pre- and during bloom, which grape mealybug is in the crawler stage. Chemiga- would restrict photosynthesis. Only treat for leaf- tion treatments with chloronicotinyl insecticides folders if extreme damage resulting in crop loss has are registered for use on grapes. Chemigation occurred in the past. Treatments would have to be treatments applied through drip irrigation can be applied as soon as the first leafrolling is noticed; effective at any time during the growing season. small larvae are the most susceptible to chemi- Irrigation water requirements for adequate distribu- cal intervention than instars. Treatment options tion of systemic insecticides vary among products. include Spinosad (Entrust), Spinetoram (Delegate Chemigation using imidacloprid is an effective WG). Follow label instructions. treatment available for grape mealybug control when it is applied in mid- to late-spring when the vineyard soil moisture is being held at or near Grape Mealybug field capacity. Chemigation with dinotefuran and thiamethoxam have proven effective when deficit Grape mealybug is a documented vector for the irrigation is practiced through summer and fall. complex of several viruses that are the causal Thiamethoxam has a 30 day PHI, so understand agents for grapevine leafroll disease (GLRD). approximate harvest dates before applications Mealybug populations should be managed follow- are made. Foliar treatments can be applied to ing the guidelines in this document. A combina- vineyards that are not irrigated by drip irrigation

19 systems. Foliar sprays of chlorpyrifos are labeled onto specified root stocks which tolerate phyllox- exclusively for dormant or delayed dormant era. However, growing conditions and established (wooly bud) applications. Research has dem- cultural practices in Washington State currently onstrated that foliar sprays of imidacloprid are make growing grapes on rootstocks impractical. not very effective at controlling grape mealybug infestations. Sprays of acetamiprid, dinotefuran, Grape phylloxera was found in a 1988, 2003, and and thiamethoxam should be directed towards 2014 survey by Washington State Department of the trunk and cordon with sufficient water and Agriculture. Both Vitis vinifera and Vitis labruscana pressure to get the pesticide into cracks and under varieties were infested in limited amounts and no loose bark. Movento should not be used in a movement to other parts of the state. delayed dormant application as it would be inef- In most areas of the world where grape phylloxera fective since it needs to be absorbed by actively has been a problem, the primary dispersal form growing tissue. Use sufficient water and pressure has been the winged stage that comes out of the to loosen bark and drive the pesticide into cracks ground and establishes colonies in galls on grape and under loose bark. Given the substantial num- leaves. Although the “leafgall” form of the phyl- ber of alternative treatments available for mealy- loxera has not been found in south central Wash- bug control, disruptive applications of chlorpyri- ington, a “crawler” or “wanderer” nymphal stage fos are no longer recommended. in the soil does a limited amount of moving and Grape mealybugs migrate from the clusters back to results in a slow spread of the infestation within the cordons and main trunk between mid-August the vineyard. and mid-September. Late summer spray applica- Movento is labeled for phylloxera, but chemical tions for mealybug control are usually ineffec- control is not recommend in Washington at this tive. If large amounts of honeydew or honeydew time. However, the use of certified, phylloxera-free and sooty mold are present on the fruit, a fungi- plants in new plantings is emphasized. cide application may aid in disease suppression. Mealybugs will not exude honeydew after leaving NOTE: To avoid problems, import and plant only the cluster. certified insect-free grapevines. Report all suspi- cious cases to the Washington State Department A new pheromone-based method has been de- of Agriculture immediately. veloped for monitoring population abundance of mealybugs. Suterra is marketing pheromone lures for grape mealybug under their Scentu- Leafhoppers rian product line. Only line registered to Suterra are Check-Mate’s. Our data indicates that traps Two species of leafhoppers can be common in should be placed in a density of at least 1 trap per Washington State vineyards. These include the 30 acres. Traps should be placed out in vineyards western grape leafhopper and the Virginia creeper in late April. Specifically males are attracted to leafhopper. In reports greater than 10 years old, these traps. Males seeking mates begin to fly in the western grape leafhopper was the predominant late April and flights peak in late May. Thresholds species in Washington State. However, in recent based on these male flights are under develop- surveys, the Virginia creeper is the predominant ment. These pheromone traps are specifically a leafhopper in Washington vineyards. Leafhop- useful tool for determining which vineyard blocks per adults and nymphs generally feed on shaded have the greatest abundance of mealybugs. These leaves. In heavy infestations, they may move to blocks should then be field-scouted directly to sun leaves. In addition to causing leaf injury, some determine if the mealybug population abundance leafhoppers may secrete honeydew, which con- warrants control actions. taminates fruit.

There are two generations per year. Adults spend Grape Phylloxera the winter in the vineyard on the fallen leaves and trash under the vines. They become active when the The grape phylloxera is related to aphids and weather becomes warm in March or April, feeding attacks the roots of Vitis vinifera grapes as well as on weeds and wild hosts until young grape leaves some Vitis labruscana grapes. Phylloxera infesta- appear. Overwintering adults lay eggs in the leaf tions have historically been devastating to grape tissue on the underside of the leaf. Eggs hatch from plantings in Europe and California. The most effec- mid-May to the end of June. New adults are active tive control is the grafting of susceptible varieties by the middle of June. Eggs of the second genera-

20 tion are laid in early July. These hatch by mid-July; The development of high mite populations is adults are active on the vines until late fall. favored by clean cultivation and dust, high temperatures, and low humidity. It is discouraged by Control is most effective if you treat vines when the use of overhead sprinkler irrigation. Outbreaks the leafhoppers are in the immature, nymphal of mites can follow the use of other pesticides in stage. Most leafhopper infestations are spotty in the pest control program. a vineyard. Spot specific treatment of Concord vineyards may be recommended, since most Research has demonstrated that 100% of the infestations are rarely of economic proportions leaves present in a vineyard are infested with on Concord. Young wine grape vineyards or wine mites when populations of mites exceed 15 mites grape vineyards being managed for canopy devel- per leaf. Injury to fruit or reduction in juice quality opment may suffer serious leafhopper injury. Foliar is minimal at mite population densities of fewer and drip chemigation with registered neonicotinyl than 30 mites per leaf after veraison. A binomial insecticides are the most effective treatments avail- sampling technique for surveying mite abundance able for control of leafhopper populations. Foliar is recommended. The presence-absence sampling sprays of registered chloronicotinyls, spirotetramat technique can be used until approximately 100% and buprofezin, if timed correctly, can provide of the leaves are infested by mites. When mites leafhopper control. are present on close to 100% of the leaves, a visual scan with a hand lens and a count of mites pres- The established treatment threshold for wine grape ent on 20 leaves per sample site is recommended vineyards is 15 leafhoppers per leaf. A sequential to quantify actual mite abundance in the vine- sampling technique should be used in sampling for yard. Research indicates that populations of mites leafhoppers. First, a presence-absence technique— below 30 mites per leaf are unlikely to damage an meaning not counting but assessing only if they otherwise healthy vineyard. Other considerations are in the vineyard—can be used until close to include the presence or absence of beneficial 100% of the leaves are infested. Presence-absence arthropods that aid in the bioregulation of spider sampling is not an efficient way of measuring leaf- mites. These beneficial arthropods include several hopper abundance at higher population densities. species of predatory mites, coccinelid ladybird When 100% of the leaves are infested, a visible beetles, lacewing larva, predatory bugs, and thrips. scan and count with a hand lens should be used to Care should be taken in choosing miticides that determine the actual density of leafhoppers present minimize harm to populations of these beneficial in the vineyard. Research has documented that arthropods. when leafhopper counts exceed 15 per collected leaf, that it is an indication that 100% of the leaves Bud Mites have at least 1 leafhopper. However, economic damage is not suspected until threshold surpass Grape bud mites overwinter as small adults inside 50 leafhoppers per leaf. grape buds. They feed on bud tissue, either killing the bud overwinter, or resulting in very short, stunted, and zig-zag like shoots in the spring. An Mites application of wettable sulfur in high water volume 2-spotted Spider Mite and Willamette Mite at the wooly-bud to budbreak stage is effective at bud mite control. Problems with spider mites in eastern Washington are confined toVitis vinifera wine grapes. Concord Grape Leaf Blister Mites (Erineum Mites) or similar American-type grapes are not affected. Willamette mite and the two-spotted spider mite Grape leaf blister mites are rarely of economic are the predominant mites observed in Washington concern in commercial vineyards. While their vineyards. Pacific mites that are commonly found characteristic galls on leaves (complete with a in California do not affect Washington grapes. white downy underside of the galls) can be alarm- ing, vines can survive a high level of infestation. Mites feed on young, tender leaves and shoot Early season sulfur applications that are typically tips, causing scarred, stunted leaves which tend applied for powdery mildew or rust mite control to cup or roll towards the undersurface. Injury are effective at controlling grape leaf blister mite. stunts shoot tips and shortens the distance Pesticide applications after blisters are visible between leaf buds. are no longer effective.

21 Rust Mite Plant-parasitic nematode management

Rust mite infestations have decreased in sever- Once a vineyard is established there are few post- ity in vineyards over the past several years. Rust plant management practices that consistently and mites are primarily a nuisance pest and late season effectively reduce plant-parasitic nematode dam- infestations are not likely to result in significant age to established vines. Therefore, prevention is economic injury. Acaricide treatments are ineffec- critical. tive on late-season populations. An early season spray of 1.5 pounds per acre of wettable sulfur has Sampling: The first step in managing plant-parasit- proven to be an effective prophylactic control for ic nematodes is to determine the species and densi- rust mites. Vineyards infested the prior summer ties of nematodes present in a field. Since nema- should be treated with sulfur early in the subse- todes are not uniformly distributed in a field, the quent spring. precision of estimating population levels increases with the number of subsamples collected. Prior to establishing a vineyard, a general rule is to collect Plant-Parasitic Nematode Control at least 20 cores along a “W” walk pattern in 2 to 5 acre area of a field. Large fields should be parti- Plant-parasitic nematodes tioned by differences in soil type and crop history. Samples should be collected in areas where root Plant-parasitic nematodes are a major economic growth occurred in the previous crop to a depth of problem in every grape production region in the 12 to 18 inches. The best time to collect samples world. The northern root-knot nematode (Meloido- is in the fall when densities of many nematode gyne hapla) caused a 43% reduction in root mass species are at their highest. Fall sampling also pro- of own-rooted Chardonnay compared to non- vides timely data on which to base management inoculated vines in a greenhouse study. However, decisions before the next season. In established the impact of nematodes on in-field grape produc- vineyards, samples should be collected within the tion in Washington is unknown. Plant-parasitic root zone concentrated under emitters and roots nematodes can cause direct and indirect damage to should be included in the sample. Collect samples a vine. Nematode feeding can cause direct damage from affected and unaffected areas of a vineyard to by stopping root elongation, killing plant tissue, make comparisons in nematode population densi- changing root growth patterns, and by removing ties. Collected samples should be kept cool until plant nutrients. These changes reduce the ability delivery to a diagnostic laboratory. of the plant to translocate nutrients and water. Indirectly, plant-parasitic nematodes can damage Planting material: Only planting stock certified plants by vectoring viruses or by increasing the free of plant-parasitic nematodes should be used severity of other plant diseases. to establish a vineyard. The use of rootstocks may be a way to manage plant-parasitic nematodes. Plant-parasitic nematodes are present in nearly Rootstocks resistant to M. hapla nematode include all natural and agricultural soils. The diversity of ‘101-14’, ‘110R’, ‘3309C’, ‘420A’, ‘Dog Ridge’, plant-parasitic nematodes in eastern Washington ‘Freedom’, ‘Harmony’, ‘Ramsey’, ‘Riparia Gloire’, vineyards was determined in surveys conducted and ‘St. George’. In western Washington where the in 2003. The most commonly encountered plant- ring nematode is common the rootstocks ‘420A’ parasitic nematodes were northern root-knot and ‘101-14’ are highly resistant to this nematodes, (Meloidogyne hapla) and dagger (Xiphinema spp.) while ‘110R’ is moderately resistant to the ring nematodes. Meloidogyne hapla is a sedentary endo- nematode. Variety selection may also be a means parasite that invades roots and causes roots to gall. to reduce the impact of plant-parasitic nematodes. Xiphinema spp. are ectoparasites, and while feeding Field microplot and greenhouse experiments indi- by these nematodes on grape roots may not result cate that white grape varieties (Chardonnay and in direct damage to the plant, several species of Riesling) are better hosts for root-knot nematode Xiphinema can transmit tomato ringspot virus to than red grape varieties (Cabernet Sauvignon, Syr- grapevines. Other plant-parasitic nematodes detect- ah, Merlot). In particular, Riesling and Chardonnay ed during the survey were lesion (Pratylenchus clones supported ten times greater reproduction spp.), ring (Mesocriconema spp.), pin (Paratylenchus of northern root-knot nematode when compared spp.), and lance (Hoplolaimus spp.) nematodes; the to Merlot clones. In a preplant situation where effect of these nematodes on vine establishment root-knot nematode population densities are high and productivity in semi-arid wine grape vineyards and other preplant treatments cannot be used, the is unknown. planting of a red grape variety may slow popula-

22 tion increase, and the potential impact of northern Scale Insects root-knot nematode on the new planting. Scale insects can damage fruit by leaving honey- Chemical: In an open field, pre-plant situation soil dew and transmitting viruses. Damage by some fumigation before planting vines is the most effec- scale insects is caused by the young crawler suck- tive method for controlling nematodes. Telone II ing "sap" from the vines and shoots. A honeydew (1,3-dichloropropene) at 35 gal/acre and Vapam HL is then formed and drips on leaves and fruit. This (metam sodium) drenched at 50 to 75 gal/acre are can result in the development of Sooty Mold (see both effective in reducing plant-parasitic nema- Diseases of Grapevines). However, another concern tode populations. If the trellis is left in place, a soil of scale insects is that some can vector Grapevine fumigant (e.g., Vapam HL) delivered through the leafroll-associated viruses (GLRaVs) (see Viruses of Grapevines). drip irrigation system may be the most cost effective control method. This is especially true because The most common scale insect in Washington is research has shown that northern root-knot nema- the European fruit lecanium scale, however, other tode is aggregated directly below drip emitters to scale insects like cottony maple scale have been a depth of 12 to 18 inches. This strategy would noted as pests. Scales can vary in size and shape not be effective in controlling dagger nematode and are often difficult to detect as they live under which is widely distributed in a vineyard down to bark and in crevices. They can be 1/16 to 1/4 inch 48 inches. Check label for rates and proper ground long, depending on the scale. The lecanium scale preparation before application of any fumigant changes the color of its rounded protective shell nematicide. from pale colored to darker brown as the season progresses. The cottony maple scale is most recog- There are several post-plant nematicides registered nized by the cottony white sticky masses that cover for use on grapes in Washington, however, the hundreds of eggs in early summer. Control for efficacy of many of these products in reducing scale insects should always be done in the spring plant-parasitic nematode population densities in when crawlers and eggs are present. this region has not been demonstrated. If a post- plant nematicide is applied to a vineyard, applica- Thrips tion timing is critical. Research has demonstrated that the mobile, infective stage of the northern Thrips are small (1/16-inch, 1.5 mm) insects, usu- root-knot nematode is highest in abundance in the ally found in association with flowers. In vine- spring and in the fall. Therefore nematicide appli- yards thrips overwinter in the leaf litter as mature cations after approximately May 1st and before females. Early in the spring, thrips develop on September 1st would potentially be less effective weeds and later move up to feed on grape foliage. than earlier or later in the season. Thrips feeding in April can severely stunt leaf and shoot growth. Injured leaves may at first glance be Cultural: Waiting one year between vine removal confused with 2,4-D or mite injury. Careful inspec- and replanting will reduce nematode population will reveal scarred midribs and veins on the tions in soil. An important component of a fallow underside of leaves. Injury to the shoot may result period is weed control since many weeds are also in shortened internodes (the distance between hosts for plant-parasitic nematodes. Proper irriga- leaves), producing a stunted appearance. Thrips may tion and fertilizer application also reduce stress scar very young berries. Later the scars restrict berry on vines and help to lessen the effect of plant- growth, producing odd-shaped or split berries. parasitic nematodes. Adult thrips are winged and may fly when the Cover crops: Plant-parasitic nematode population leaves are disturbed. However, the wingless, yellow densities may be reduced even further by plant- to yellow-orange nymphs may be observed. Control ing a cover crop in the area to be planted to vines. of thrips will bring resumed normal growth of Cover crops that have received attention in Wash- leaves and shoots. Earlier injury remains as a record ington for the management of nematodes include of the infestation. High populations of thrips can mustards, arugula, and sudangrass. When using a be associated with high spider mite populations. cover crop to manage nematodes it is important to Insecticidal control of thrips infestations has properly identify the target nematode species since proven difficult. Spinosad can provide control cover crops will vary in effectiveness depending in warm weather conditions. Pyrethroids are not upon the nematode species. recommended for thrips control on wine grapes.

23 PEST MANAGEMENT PROGRAM FOR GRAPEVINES Material per Acre Treated Min. Days Pests to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials PRE-PLANT Nematodes 1. 1,3-dichloropropene 35 gallons Check label for re-entry time for planting. Excessive use (Telone II) harmful 2. metam sodium 50–75 gallons Check label for re-entry time for planting. Excessive use (Vapam HL) harmful POST-PLANT Nematodes 1. Myrothecium 15 pounds Labeled for organic production, microbial metabolic Safe verrucaria (DiTera) byproduct. 2. spirotetramat 6.0–8.0 fluid ounces 7 Do not apply more than 12.5 fluid ounces per acre (Movento) per season. Use a non-ionic, high quality adjuvant to obtain effective full canopy applications and uptake through tissues. Interval between applications is 30 days. Needs to be absorbed by green leaf or stem tissue, and translocated by the plant to the sucking insect. 3. Rotational crops such as mustards, arugulas, and sudangrass can suppress populations of nematodes. However, you must know the nematode species present, as certain crops are more effective at suppressing specific nematodes than others. Thus, these crops are best if grown in a mix. DORMANT TO DELAYED-DORMANT (WOOLY BUD) Scale insects 1. horticultural mineral 4.0–6.0 gallons per Apply late March to early April. Direct spray to trunk Moderately oil (Damoil) 200–300 gallons and main cordons. Do not apply horticultural mineral harmful water/acre; 1.0–2.0 oil at these concentrations after bud break with green gallons per 200–300 tissue. gallons water/acre when tank-mixed with other pesticides DELAYED-DORMANT (WOOLY BUD) TO BUDBREAK Scale insects 1. horticultural mineral 0.75 gallons per 100 May give only marginal control. Moderately oil (Damoil) gallons water/acre harmful Cutworms 1. fenpropathrin Follow label Barrier spray to trunk and posts in early- to mid-March. Extremely (Danitol 2.4 EC) instructions hazardous 2. bifenthrin Follow label Barrier spray to trunk and posts in early- to mid-March. Extremely (Brigade 2EC) instructions hazardous 3. beta-cyfluthrin 2.4–3.2 fluid ounces 3 Barrier spray to trunk and posts in early- to mid-March. Extremely (Baythroid XL) hazardous 4. zeta-cypermethrin 2.0–4.0 fluid ounces 1 Barrier spray to trunk and posts in early- to mid-March. Extremely (Mustang Maxx) hazardous 5. chlorantraniliprole 3−4.5 ounces per 1 Do not apply more than 9 ounces Altacor or 0.2 Safe (Altacor) acre pounds of active ingredient of chlorantraniliprole containing products per acre per crop per season. The minimum interval between treatments is 7 days.

24 PEST MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Days Pests to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials BUDBREAK TO PREBLOOM (15 inch Shoot Growth) Scale insects 1. horticultural mineral 0.75 gallons per 100 May give only marginal control. Moderately oil (Damoil) gallons water/acre harmful Cutworms 1. spinosad 4.0–8.0 fluid ounces 7 More effective when temperatures exceed 70°F. Do Safe (Success) not use more than 0.45 pound of active ingredient per acre per season. 2. spinetoram 3.0–5.0 ounces 7 (Delegate) 3. chlorantraniliprole 3−4.5 ounces per 1 Do not apply more than 9 ounces Altacor or 0.2 Safe (Altacor) acre pounds of active ingredient of chlorantraniliprole containing products per acre per crop per season. The minimum interval between treatments is 7 days.

Thorough coverage is essential to achieve best results. Select a spray volume appropriate for the size of vines and density of foliage. For best results apply 100−150 gallon water per acre. Do not apply dilute applications of more than 200 gallon water per acre. Do not apply less than 30 gallon water per acre. Grape 1. buprofezin 9.0–12.0 ounces 7 Target young nymphs on vines and leaves. Make no Safe leafhopper, (Applaud 70DF) more than 2 applications per season. Grape mealybug 2. potassium salts 2 gallons/100 gallon 0 Apply M-Pede in 100 to 200 gallons of water per acre Moderately of fatty acids spray (REI = 12 from mid-June to late July. harmful (M-Pede) hrs) 3. imidacloprid 1.0–1.4 fluid ounces 0 Moderately (Admire Pro) (REI = 12 harmful hrs) 4. dinotefuran Foliar: 1.0–3.0 ounces 1 Regardless of application method do not apply more Moderately (Venom) than a total of 12 oz Venom per acre per season. Foliar harmful Soil: 5.0–7.5 ounces 28 application is limited to 6 ounces and soil application is limited to 7.5 ounces per acre per season. 5. thiamethoxam 8.0–17.0 fluid ounces 60 Chemigate via drip irrigation. Follow label instructions. (Platinum) Sprays should be directed towards the trunk and cordons. Use sufficient water and pressure to loosen bark and drive the pesticide into cracks and under loose bark. 6. spirotetramat 6.0–8.0 fluid ounces 7 Do not apply more than 12.5 fluid ounces per acre (Movento) per season. Use a non-ionic, high quality adjuvant to obtain effective full canopy applications and uptake through tissues. Interval between applications is 30 days. It needs to be absorbed by green leaf or stem tissue, and translocated by the plant to the sucking insect. Thrips 1. spinosad 4.0–8.0 fluid ounces 7 More effective when temperatures exceed 70°F. Do Safe (Success) not use more than 0.45 pound of active ingredient per acre per season. Needs to be absorbed by green leaf or stem tissue, and translocated by the plant to the sucking insect.

25 PEST MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Days Pests to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials BLOOM TO PEASIZE FRUIT Grape 1. imidacloprid Soil: 7.0–14.0 fluid 30 Maximum foliar rate allowed is 2.8 fluid ounces per Moderately leafhopper, (Admire Pro) ounces acre per year. Maximum soil rate allowed is 14 fluid harmful Grape ounces per acre per year. Drip-applied imidacloprid mealybug Foliar: 1.3–1.4 fluid 0 should not be used when vines are also under water ounces (REI = 12 stress (regulated deficit irrigation) as the product will hrs) not be taken up by the plant. 2. spirotetramat 6.0–8.0 fluid ounces 7 Do not apply more than 12.5 fluid ounces per acre (Movento) per season. Use a non-ionic, high quality adjuvant to obtain effective full canopy applications and uptake through tissues. Interval between applications is 30 days. Needs to be absorbed by green leaf or stem tissue, and translocated by the plant to the sucking insect. 3. buprofezin 9.0–12.0 ounces 7 Target young nymphs on vines and leaves. Make no Safe (Applaud more than two applications per season. 70DF) 4. dinotefuran Foliar: 1.0–3.0 ounces 1 Regardless of application method do not apply more Moderately (Venom) than a total of 12 oz Venom per acre per season. Foliar harmful Soil: 5.0–7.5 ounces 28 application is limited to 6 ounces and soil application is limited to 7.5 ounces per acre per season. Sprays should be directed towards the trunk and cordons. Use sufficient water and pressure to loosen bark and drive the pesticide into cracks and under loose bark. 5. acetamiprid 1.1–2.3 ounces 3 Sprays should be directed towards the trunk and Moderately (Assail 70WP) cordons. Use sufficient water and pressure to loosen harmful bark and drive the pesticide into cracks and under loose bark. Only two applications per season are allowed. 6. thiamethoxam 8.0–17.0 fluid ounces 60 Sprays should be directed towards the trunk and Moderately (Platinum) cordons. Use sufficient water and pressure to loosen harmful bark and drive the pesticide into cracks and under loose bark. Only two applications per season are allowed. 7. thiamethoxam 1.5–3.5 ounces 5 Moderately (Actara) harmful PEASIZE FRUIT TO VÉRAISON Grape 1. imidacloprid Soil: 7.0–14.0 fluid 30 Maximum foliar rate allowed is 2.8 fluid ounces per Safe mealybug, (Admire Pro) ounces acre per year. Maximum soil rate allowed is 14 fluid Grape ounces per acre per year. Drip-applied imidacloprid leafhopper Foliar: 1.3–1.4 fluid 0 should not be used when vines are also under water ounces (REI = 12 stress (regulated deficit irrigation) as the product will hrs) not be taken up by the plant. 2. buprofezin 9.0–12.0 ounces 7 Target young nymphs on vines and trees. Make no Safe (Applaud 70DF) more than two applications per season. 3. dinotefuran Foliar: 1.0–3.0 ounces 1 Regardless of application method do not apply more Moderately (Venom) than a total of 12 oz Venom per acre per season. Foliar harmful Soil: 5.0–7.5 ounces 28 application is limited to 6 ounces and soil application is limited to 7.5 ounces per acre per season. Sprays should be directed towards the trunk and cordons. Use sufficient water and pressure to loosen bark and drive the pesticide into cracks and under loose bark.

26 PEST MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Days Pests to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials PEASIZE FRUIT TO VÉRAISON (continued) Grape 4. acetamiprid 1.1–2.3 ounces 3 Sprays should be directed towards the trunk and Moderately mealybug, (Assail 70WP) cordons. Use sufficient water and pressure to loosen harmful Grape bark and drive the pesticide into cracks and under leafhopper, loose bark. Only two applications per season are (continued) allowed. 5. spirotetramat 6.0–8.0 fluid ounces 7 Do not apply more than 12.5 fluid ounces per acre (Movento) per season. Use a non-ionic, high quality adjuvant to obtain effective full canopy applications and uptake through tissues. Interval between applications is 30 days. Needs to be absorbed by actively growing green leaf or stem tissue, and translocated by the plant to the sucking insect. 6. thiamethoxam 8.0–17.0 fluid ounces 60 Sprays should be directed towards the trunk and Moderately (Platinum) cordons. Use sufficient water and pressure to loosen harmful bark and drive the pesticide into cracks and under loose bark. 7. thiamethoxam 1.5–3.5 5 Moderately (Actara) ounces harmful 8. flupyradifurone 21.0–28.0 fluid 30 Do not apply more than 28.0 fluid ounces per acre per (Sivanto 200SL) ounces season. Soil applied. Mites 1. bifenazate 0.75–1.0 pound 14 Safe (Acramite 50WS) 2. fenpyroximate 2.0 pints 14 Apply before the mite population reaches an outbreak Safe (FujiMite 5EC) population density. 3. abamectin 1.75–3.5 fluid ounces 28 Always use with a nonionic surfactant and sufficient Moderately (Agri-Mek SC) gallonage for coverage. harmful 4. spirodiclofen 16.0–34.0 fluid 14 Apply in a minimum of 50 gallons/acre and fully cover (Envidor 2SC) ounces the wood and foliage. One application per year is allowed. 5. propargite (Omite 5.0–9.0 pounds 21 A problem only on wine grapes (V. vinifera). Safe 30WS) Thrips 1. spinosad 4.0–8.0 fluid ounces 7 More effective when temperatures exceed 70˚F. Do not Safe (Success) use more than 0.45 pounds of active ingredient per acre per season.

27 PEST MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Days Pests to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials VÉRAISON TO PREHARVEST Grape 1. imidacloprid Soil: 7.0–14.0 fluid 30 Maximum foliar rate allowed is 2.8 fluid ounces per Safe mealybug, (Admire Pro) ounces acre per year. Maximum soil rate allowed is 14 fluid Grape ounces per acre per year. Drip-applied imidacloprid leafhopper Foliar: 1.3–1.4 fluid 0 should not be used when vines are also under water ounces (REI = 12 stress (regulated deficit irrigation) as the product will hrs) not be taken up by the plant. 2. buprofezin 9.0–12.0 ounces 7 Target young nymphs on vines and leaves. Make no Safe (Applaud 70DF) more than two applications per season. 3. dinotefuran Foliar: 1.0–3.0 ounces 1 Regardless of application method do not apply more Moderately (Venom) than a total of 12 oz Venom per acre per season. Foliar harmful Soil: 5.0–7.5 ounces 28 application is limited to 6 ounces and soil application is limited to 7.5 ounces per acre per season. Sprays should be directed towards the trunk and cordons. Use sufficient water and pressure to loosen bark and drive the pesticide into cracks and under loose bark. 4. acetamiprid 1.1–2.3 ounces 3 Sprays should be directed towards the trunk and Moderately (Assail 70WP) cordons. Use sufficient water and pressure to loosen harmful bark and drive the pesticide into cracks and under loose bark. Only two applications per season are allowed. 5. spirotetramat 6.0–8.0 fluid ounces 7 Do not apply more than 12.5 fluid ounces per acre (Movento) per season. Use a non-ionic, high quality adjuvant to obtain effective full canopy applications and uptake through tissues. Interval between applications is 30 days. Needs to be absorbed by actively growing green leaf or stem tissue, and translocated by the plant to the sucking insect. 6. thiamethoxam 8.0–17.0 fluid ounces 60 Note the 60 day pre-harvest interval may limit harvest Moderately (Platinum) dates if applied at this time of year. Sprays should be harmful directed towards the trunk and cordons. Use sufficient water and pressure to loosen bark and drive the pesticide into cracks and under loose bark. 7. thiamethoxam 1.5–3.5 5 Moderately (Actara) ounces harmful 8. flupyradifurone 21.0–28.0 fluid 30 Do not apply more than 28.0 fluid ounces per acre per (Sivanto 200SL) ounces season. Soil applied.

28 DISEASES OF GRAPEVINES

Several types of disease organisms, in addition to Disease incidence is especially high in older vine- nematodes, can affect grapes. While a number of yards where large pruning wounds were made to potential problems exist, only a few are of econom- alter the training system. Most commercial grape ic importance in Washington State. cultivars are affected by this disease. Both young and old vines are susceptible. However, Eutypa die- WSU has an online system called AgWeatherNet back is generally not found in vines younger than that uses weather data to detect and alert users 5 years old. when conditions are favorable for disease outbreak (http://weather.wsu.edu). Check AgWeatherNet Symptoms of Eutypa dieback include stunting of frequently during the growing season to see if spring shoot growth, yellowing and cupping of conditions are favorable for disease outbreaks. In newly emerged leaves, shedding of blossom clusters, addition, see Field Guide for Integrated Pest Manage- vascular discoloration, and cankers in stems associ- ment in Pacific Northwest Vineyards (PNW644) for a ated with old pruning wounds. In advanced stages, visual key to several grape diseases. part or all of a vine will die. Symptoms are best seen in the spring when shoots of healthy grapevines are 10–15 inches long. Later in the growing season Trunk and Root Diseases affected shoots are stunted, and leaves of infected vines become tattered and scorched. Clusters on in- Crown Gall fected shoots are poorly developed and often wither and drop. Foliage of infected vines may be covered This bacterial disease is widespread. Crown gall has and masked by the foliage of healthy grapevines. An especially plagued young vines and is associated important diagnostic symptom of Eutypa dieback with freezing injury. Low temperatures, particularly on the trunk or arms is a canker associated with a occurring early in winter, lead to high incidence of pruning wound. However, the bark must be peeled crown gall. away to see the canker. It is also common to find The bacterium infects plants through wounds one side of a vine dead or with disease symptoms (such as those that occur during propagation of and the other side appearing healthy. cuttings) or through root lesions. The bacterium Infection occurs when airborne spores of the fungus survives systemically in symptomless grapevines come in contact with fresh pruning wounds during and can be carried in dormant grape cuttings used or immediately following rainstorms. Spores germi- in the propagation of plants. nate on the wound, and the fungus grows into the wood and produces a canker. Symptoms may not The first symptoms are swellings on wood that is appear on diseased vines for more than 3 years after more than 2 years old. Young galls are soft, creamy infection. Cankers expand lengthwise in both direc- to greenish, with no bark or covering. As the tissue tions from the wound and will eventually girdle and ages, it darkens to brown. The surface can become kill arms or trunk of infected vines in 5 to 10 years. hard and very rough and black as it dies. Losses due to Eutypa dieback can be reduced by Planting certified stock reduces the potential identifying and removing portions of diseased risk of crown gall as these plants are visually free vines before the fungus spreads extensively in the of gall symptoms. Use certified stock that came infected vine. In the spring, when disease symp- from a Foundation Program that uses microtip toms are most noticeable (shoots of healthy vines propagation. Protect vines from freezing injury. will be 10–15 inches long), is a good time to locate Avoid wounding plants during cultivation and and mark the diseased vines. Diseased wood should discard plants with galls. Soil fumigation has be removed 4 to 6 inches below the canker and a not been effective in eradicating the crown gall new, healthy shoot trained into position. Remove bacterium. (See http://wine.wsu.edu/research- the diseased wood after peeling the bark and trac- extension/ for more information on Crown Gall.) ing the canker or by making a series of successive cuts until a final cut is made in healthy tissue with Eutypa Dieback all brown, discolored wood removed. If the canker has grown below ground level, remove and replace Eutypa dieback of grapevine is an important grape the vine. Replacement may be quicker in this situ- disease in Washington and throughout the world. ation if a shoot of an adjacent vine is layered and

29 trained into position than if a cutting or rooting Remove cluster mummies (infected dry clusters) were planted. The fungus does not persist in soil, from the vines at pruning and disc into the soil. and it is not spread by pruning tools. Vines of susceptible varieties should not be sprinkler irrigated once the fruit is mature. Summer prun- In addition, double pruning, or mechanically pre- ing or leaf removal of vigorous vines to increase air pruning early in the dormant period, followed by circulation around clusters and improved spray pen- a hand-pruning later in the dormant period, can etration may reduce disease incidence and severity. also reduce infection risk of the main trunk, by removing segments of cane tissue that may have Protect susceptible varieties in vineyards that have a been recently infected. history of bunch rot with fungicides. Vangard WG and Scala SC (FRAC 9) and Elevate SC (FRAC 17) are Pruning wounds become resistant to infection about three relatively new and effective fungicides. Rovral 2 to 4 weeks after pruning. The time required for a (FRAC 2) is still a widely used and effective fungi- wound to become resistant depends on when the cide. Fungicide applications are most important dur- pruning is done. Pruning cuts made in December ing bloom and immediately before bunch closure. remain susceptible for a longer time than cuts made Additional applications may be necessary during in late winter and early spring. Therefore, waiting to prolonged periods of wet weather. Because fungi- prune until late winter and early spring may be bet- cides can inhibit yeast fermentation, use them with ter than pruning earlier, if the weather is not rainy. caution within 1 month of harvest on wine grapes.

Applications of latex paint and other wound dress- Some fungicides and fungicide premixes provide ings on pruning wounds have not been effective in control of both powdery mildew and bunch rot reducing infections. when applied according to label instructions. These should be considered at critical times. For Phomopsis Cane and Leaf Spot additional control information see Botrytis Bunch Rot in Commercial Washington Grape Production: This fungus disease attacks leaves, shoots, rachis, Biology and Disease Management (FS046E). and berries of grapes in many parts of the country. It produces small brown to black spots, usually with yellow margins on leaves. Portions on leaves Powdery Mildew may die if large numbers of spots develop; infec- This is one of the most economically important tions on leaf petioles will cause the leaves to turn diseases on wine grapes in the state of Washington. yellow and abscise. Spots on shoots are oblong and It attacks all green tissues of the vine, but is most generally at the basal portion; spots on flower clus- damaging to leaves and green fruit, covering them ter stems are similar to those on leaves and shoots. with a gray, powdery layer of fungal threads and Wet weather during early shoot growth favors spores. Affected fruit often cracks, allowing second- disease development. To date, it has not been an ary rots to become established. economic problem in Washington State. This disease rarely damages the American Vitis labr- Foliar and Fruit Diseases uscana varieties, such as Concord, and only slightly damages hybrid grapes. Conversely, European Vitis Botrytis Bunch Rot vinifera varieties are highly susceptible. The first mildew colonies often appear on the undersides Botrytis bunch rot can produce significant yield of leaves close to the bark. Infection occurs in and quality losses in tight-clustered wine varieties response to early season rains and symptoms are such as Riesling and Chenin Blanc. In addition to usually evident by June. desiccation and rotting, the disease may provide an entrance for secondary microorganisms that cause The fungus survives winter as cleistothecia (minute additional fungal rots or bacterial sour rots. fungal fruiting bodies) in bark crevices and leaf litter. Each viable cleistothecium contains numerous Symptoms consist of brownish rotted fruit, usu- spores known as ascospores. The ascospores persist ally with tufts of gray fungal growth (hyphae and (and the risk of primary infection exists) through spores) on the berry surface. The fungal growth bloom. Ascospore release and primary infection usually begins at skin cracks and then spreads over require at least 0.1 inch (2.5 mm) of moisture at the entire berry, giving a gray moldy appearance. temperatures of 50°F or greater. Ascospores are Fungal growth and spread are enhanced by rain dispersed in wind currents and land on leaves, and prolonged overhead sprinkler irrigation. where they germinate, giving rise to microscopic

30 mildew colonies. Conidia, the asexual and far more Committee (FRAC) group number or code. The FRAC numerous spore type, are produced in the primary code represents the mode of action of the fungicide. mildew colonies. Dispersed by wind to foliage This information is helpful when designing a and fruit, conidia infect and produce subsequent fungicide program that conforms to FRAC resistance secondary mildew colonies. This process repeats management guidelines. It is important to remember through the growing season. Powdery mildew is that if a pathogen population develops resistance promoted by overcast weather and high humidity. to fungicides within a FRAC group, it is likely to be resistant to all members of that group. Resistance is The grape powdery mildew fungus can develop more likely to develop if the pathogen is frequently resistance to many popular and highly effective fun- treated with one or multiple fungicides within a gicides, most notably the DMI and Qol (strobilurin) given FRAC group. Included in the table are members compounds. To prevent resistance, incorporate sev- of the fungicide classes (or FRAC Groups) known eral different fungicidal modes of action into the as benzophenones (metrafenone, Group U8), DMI spray program. Do not exceed three applications per (demethylation inhibitors, Group 3), QoI (quinone year of any systemic fungicide and do not apply outside inhibitors; previously called strobilurins, any specific class more than twice in sequence. Group 11), quinolines (quinoxyfen, Group 13), Management should include: sulfur (Group M2), various “biological” fungicides (Group 44), SDHI (succinate dehydrogenase • use of a training system that allows good air inhibitors, Group 7), petroleum derived spray oils, movement through the canopy and prevents and potassium bicarbonate. Petroleum spray oils and excess shading; potassium bicarbonate are listed as “Not Classified” • use of a recommended spray program. (NC) by FRAC. Several products are formulations CAUTION: Sulfur can cause severe or “premixes” of two different fungicide classes, burning of the foliage. See Powdery Mil- modes of action, of FRAC groups. Consult product dew in Eastern Washington Commercial Grape labels for appropriate rates and spray intervals. The Production: Biology and Disease Management resistance risk is product-dependent (Table 2). All of (EM058E), and Powdery Mildew in Western the aforementioned “new” products have performed Washington Commercial Grape Production: well in efficacy trials at WSU-IAREC. Biology and Disease Management (EM059E); The availability of “premix” or combination • employ techniques such as shoot thinning fungicide formulations is a relatively recent trend and leaf stripping that improve light and in agriculture. The grape toolbox contains several spray penetration in the fruiting zone; of these product types: Inspire Super (difenocon- • particular vigilance during the prebloom azole + cyprodinil), Luna Experience (fluopyram + period through pea-size berries; tebuconazole), Pristine (pyraclostrobin + boscalid), • consult grape powdery mildew models on Quadris Top (difenoconazole + azoxystrobin) and AgWeatherNet (http://weather.wsu.edu) for Unicorn (tebuconazole + sulfur). Both active ingre- favorable environmental conditions; and dients in these compounds, with the exception of Inspire Super, have activity against powdery • proper irrigation management. mildew (only the difenoconazole component of Managing resistance to powdery mildew Inspire Super is active against the fungus). When both modes of action have activity against the tar- fungicides get organism, some level of resistance management Washington wine grape growers have several is built into the products provided that they are new fungicides at their disposal for managing used rationally. The use of “premix” types of prod- powdery mildew. New products included in the ucts can provide better disease control, provide powdery mildew toolbox include: Inspire Super disease control security if there is field resistance to (difenoconazole + cyprodinil), Unicorn (tebuconazole one of the two active ingredients, and help prevent + sulfur) and Vivando (metrafenone), and Mettle resistance if there is not. (tetraconazole). Inspire Super, along with the existing products Flint (trifloxystrobin) and Pristine FRAC Group 11 Resistance (pyraclostrobin + boscalid), provide the added benefit of also controlling Botrytis bunch rot, when applied In 2016 and 2017, surveys in Oregon and Wash- at the appropriate rates. A non-exhaustive list of ington vineyards that lost powdery mildew disease powdery mildew compounds is included in this control early in the season showed that the pow- section under Table 2. The table includes fungicide dery mildew present in almost all of those vineyards class information and Fungicide Resistance Action tested was resistant to FRAC 11 fungicides.

31 Table 2. Common fungicides used in PNW vineyards, with associated FRAC codes and fungicide resistance risk. PM = powdery mildew; BBR = Botrytis bunch rot; Mod. = moderate; NA = Not appropriate for the target pest (Powdery Mildew or Botrytis); NT = Not tested by WSU in eastern Washington; gray shading = Not registered for that pest. Registered Fungicide Trade Name FRAC Resistance PM Chemical Name7 Class for Example1 Group Risk Efficacy3 Botrytis Rovral, Nevado iprodione Dicarboximide 2 High Yes Rally 40WSP myclobutanil DMI 3 Mod. ** Orius 20AQ, Tebuzol 45DF tebuconazole DMI 3 Mod. ** Mettle tetraconazole DMI 3 Mod. ** Procure 480SC triflumizole DMI 3 Mod. ** Unicorn tebuconazole / sulfur2 DMI/Sulfur 3 / M2 Mod. / Low ** Inspire Super difenoconazole2 / cyprodinil DMI/AP 3 / 9 Mod. / High *** Yes Quadris Top difenoconazole2 / DMI/QoI 3 / 11 Mod. / High *** azoxystrobin Aprovia benzovindiflupyr SDHI 7 Mod. / High *** Endura boscalid SDHI 7 High / Mod. ** Yes Luna Experience fluopyram4 / tebuconazole SDHI/DMI 7 / 3 High / Mod. *** Yes Vangard WG cyprodinil AP 9 High NA Yes Scala SC pyrimethanil AP 9 High Yes Switch 62.5 WG cyprodinil / fludioxonil AP/PP 9 / 12 High / Mod. NA Yes Abound azoxystrobin QoI 11 High ** Yes Sovran kresoxim-methyl QoI 11 High ** Yes Flint trifloxystrobin2 QoI 11 High *** Yes Pristine pyraclostrobin2 / boscalid QoI/SDHI 11 / 7 High / High *** Yes Quintec quinoxyfen azanaphthalene 13 Mod. *** (quinoline) Botran 75 W DCNA (dicloran) AH 14 Low-Mod. Yes Elevate fenhexamid SBI Class 3 17 Mod. NA Yes Ph-D polyoxin-D zinc salt Polyoxin 19 Mod. * Yes Actinovate-AG Streptomyces lydicus Biological None Low * Yes Serenade Max Bacillus subtilis Biological 44 Low * Yes Sonata Bacillus pumilus Biological 44 Low * Several formulations sulfur2 Inorganic M2 Low ** Ziram ziram Dithiocarbamates M3 Low NA Yes Dithane, Manzate, mancozeb Dithiocarbamates M3 Low Yes Penncozeb Regalia extract of Reynoutria Plant Extract P5 Low * Yes sachalinensis Torino cyflufenamid phenyl-acetamide U6 Mod. ** Vivando metrafenone aryl-phenylketone 50 Mod. *** Prolivo 300 SC pyriofenone aryl-phenylketone U8 Mod. *** Kaligreen potassium bicarbonate none listed NC Low *5 M-Pede Soap, potassium laurate soap None Low ** JMS Stylet Oil, Neem Oil, Mineral oils, organic oils, oil NC Low **6 PureSpray Green plant oils 1Fungicide Trade Names are for example purposes only and does not indicate an endorsement of a specific brand or company. Some active ingredients are available under multiple trade names. 2These products have varying degrees of phytotoxicity (leaf burning) on Vitis labruscana ‘Concord’. 3Efficacy ratings: * = poor control; ** = moderate control; *** = excellent control 4Do not use on grapes that may be used for purposes other than wine (i.e., table or juice grapes). 5Eradicant activity good, protective activity poor 6Eradicant activity good, protective activity good 7Boldfaced chemical names are those that fall into the FRAC 11 category. FRAC 11 fungicide resistance has been documented in some vineyards in Washington.

32 FRAC 11 resistance is all-or-nothing; but regional protective, rather than reactive, manner. It is far efforts towards the smart use of this fungicide group easier to prevent powdery mildew than to cure it. can help reduce or eliminate the spread of resistant Additional guidelines include limiting the number fungi. These products are important in both the of applications of individual modes of action per powdery mildew and Botrytis bunch rot manage- season and limiting sequential applications. Do ment arsenal, so proper management of this devel- not tank mix or alternate fungicides with the same oping resistance is critical for our industry. FRAC number in a spray program. Medium risk compounds such as DMI (Group 3), SDHI (Group Our current recommendations for managing 7), and quinoline compounds (Group 13) should resistance are: be applied no more than 2 times per season and 1. If you haven’t ordered FRAC 11 products, then never in sequence. High risk QoI (FRAC Group 11) avoiding their use for a season is advisable. compounds or premixed formulations containing However, avoidance practices like this work them (Flint, Sovran, Pristine, and Abound) fungi- best on a region-wide scale. cides should be preferably alternated 1:1 with other modes of action or Groups. It is preferable to make 2. If you have already ordered FRAC 11 products, only one application of any resistance-prone com- then we recommend limiting their use to 1x pound and then switch to a fungicide from a dif- per season. Tank mix with a compatible contact ferent class or FRAC group. Never use two Group fungicide (e.g., sulfur) to help reduce resistance 11 applications in sequence. When Group 11 com- development. Please note that appropriate water pounds are used as a solo product (Abound, Flint, volumes will be needed when tank mixing with and Sovran), the number of applications should be a contact product. At full canopy, this may no greater than 1/3 of the total number of fungi- mean that 75 gallons/acre is warranted. Please cide applications per season. In programs utilizing check compatibility of products prior to appli- tank mixes or pre-mixes of a Group 11 fungicide cation on a vineyard. with a fungicide of another group (e.g., Pristine), 3. If you have to use more than one FRAC 11 the number of Group 11 fungicide QoI-containing spray (and products for those sprays are already applications should be no more than 1/2 of the ordered), please try to limit applications to total number of fungicide applications per season. no more than 2 total sprays, and never spray It also helps to tank-mix fungicides from different those products containing FRAC 11 fungicides groups that are both effective against powdery mil- back-to-back in a spray program. Practice tank- dew. Sulfur is a relatively inexpensive and effective mixing as described in #2. Try to avoid applying companion product for mixing with medium- or any FRAC 11 fungicides later in the growing high-risk compounds. Try to include it in every season (after bunch closure). This includes FRAC spray tank aimed at powdery mildew if permit- 11 products used for Botrytis bunch rot manage- ted according to usage instructions on product ment. In future years, try to follow guidelines labels. Always follow label instructions pertaining discussed in #1 or #2. to application rates and intervals and always use a properly calibrated sprayer and sufficient spray THESE RECOMMENDATIONS ARE FOR VINEYARDS volume to provide good coverage. THAT DO NOT HAVE RESISTANT POPULATIONS. If your vineyard has confirmed resistance to a FRAC Powdery mildew is an early-season disease. fungicide group, please do not use that FRAC fun- The first management application should gicide group in your sprays, as they will likely pro- be completed by no-later than 10 inch vide you with little to no control. Current research shoot growth. The most critical period for pow- is underway on when and how these fungicides dery mildew control on clusters is from immediate can be re-introduced into a spray regime. prebloom to three weeks postbloom. Our most effective compounds should be utilized during this General Resistance Management period. Bloom is also a critical period for the establishment of Botrytis bunch rot in the vineyard. As General resistance management guidelines include noted above, several of our highly effective powdery the incorporation of cultural practices that lower mildew fungicides/fungicide premixes (Flint, Inspire disease pressure. Cultural practices such as vigor Super, and Pristine) provide (when used at appropri- management, shoot removal and positioning, and ate rates) activity against both powdery mildew and leaf removal lower disease pressure and improve Botrytis bunch rot. These compounds are logical for spray penetration. The incorporation of these deployment during bloom but remember to keep practices serves to lower selection pressure on applications of QoI (Group 11) compounds, or mix- pathogen populations. Always use fungicides in a tures containing them, to a minimum.

33 Sooty Mold

When honeydew (an insect excretion; see also Mealybugs and Scales) covers the vines, leaves, and fruit, a black fungus may develop on the honeydew. While this fungus rarely causes any direct damage, it can destroy the economic value of juice grapes for processing.

The primary control of this problem requires controlling the insects that produce honeydew.

34 DISEASE MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Diseases Days to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials BUDBREAK TO PREBLOOM (15 inch Shoot Growth) Powdery 1. azoxystrobin (Abound) 10.0–15.5 fluid 14 Azoxystrobin is phytotoxic to certain apple Safe mildew ounces varieties. Read and follow resistance management recommendations on label. RESISTANCE RECOMMENDATION: Tank mix with a contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 2. trifloxystrobin (Flint) 1.5–2.0 ounces 14 Do not use Flint on juice grapes. RESISTANCE Safe RECOMMENDATION: Tank mix with a contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 3. kresoxim-methyl 3.2–4.8 ounces 14 RESISTANCE RECOMMENDATION: Tank mix with a Safe (Sovran) contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 4. myclobutanil (Rally 3.0–5.0 ounces 14 Begin application at prebloom (12- to 18-inch canes), Safe 40WSP) and continue on a 14- to 21-day interval. Use higher rates on susceptible varieties or under heavy disease pressure. Do not apply more than 1.5 pounds (0.6 pound of active ingredient) per acre per year. Place myclobutanil into solution before adding oil. 5. tebuconazole 8.6 fluid 14 Maximum 68.8 ounces per acre per season. Safe (Orius 20AQ) ounces 6. quinoxyfen 3.0–4.0 fluid 21 Apply Quintec before visible symptoms of powdery Safe (Quintec) ounces mildew appear. Do not make more than 5 applications per year. Minimum interval is 14 days. Do not apply more than 6.6 fluid ounces per acre per application or more than 33 fluid ounces per acre per year. 7. pyraclostrobin + 8.0–12.5 14 Begin applications at bud break or prior to onset of Safe boscalid (Pristine) ounces disease. Do not make sequential applications of a fungicide containing a FRAC 11 product. Alternate to a fungicide with a different mode of action (FRAC group). 8. petroleum / mineral / 1–2% 0 Do not mix oil with sulfur or apply either compound Excessive use paraffinic oil (REI = 4 within 3 weeks of the other. Apply at 10- to 14-day harmful hrs) intervals. Not all oils are the same purity or have the same PHI for table grapes. The 1–2% recommended rate is for pure (98%+) active ingredient. Do not use on juice grapes. 9. micronized flowable See label. no PHI Sulfur has both contact and volatile activity when Excessive use sulfur (Microthiol given (REI applied at temperatures between 68°F and 85°F. When harmful Disperss) = 24 hrs) temperatures are colder, it works as a contact product only. When temperatures are warmer, there is risk of phytoxicity. Some phytoxic effects on juice grapes. 10. sulfur dust 5.0–10.0 no PHI Begin sulfur applications when shoots are 6 to 8 inches Excessive use (Dusting Sulfur) pounds given (REI long. Make a second application when shoots are 12 to harmful = 24 hrs) 15 inches long, and a third about 14 days later. Repeat at 10- to 14-day intervals to protect new growth. 11. potassium 2.5 pounds 0 (REI = Use in 100 gallons of water. Excessive use bicarbonate 4 hrs) harmful (Kaligreen) 12. metrafenone 10.3–15.4 fluid 14 days Do not make more than 3 applications per season. Do Safe (Vivando) ounces not apply more than 46.2 ounces of product per acre per crop.

35 DISEASE MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Diseases Days to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials BUDBREAK TO PREBLOOM (15 inch Shoot Growth) (continued) Powdery 13. difenoconazole + 16–20 fluid 14 days Also provides control of Botrytis bunch rot. Do not apply Safe mildew cyprodinil ounces more than 80 ounces per acre of Inspire Super per (continued) (Inspire Super) season. Do not apply more than 1.4 pounds of active ingredient/acre of a cyprodinil containing product. Do not treat grapes such as Thompson Seedless and Concord which may be used for purposes other than wine. 14. tetraconazole 3.0–5.0 fluid 14 days Do not apply more than 10 ounces of Mettle per acre Safe (Mettle) ounces per year. 15. tebuconazole + sulfur 1.75 to 2.5 14 days Do not apply more than 20 pounds of Unicorn per acre Unknown (Unicorn) pounds per crop season. Do not mix Unicorn with other DMI fungicides. Do not make applications less than 7 days apart. 16. azoxystrobin + 12–14 fluid 14 Do not apply to Concord grapes and Thompson Safe difenoconazole ounces Seedless. Azoxystrobin is extremely toxic to certain (Quadris Top) apple varieties. Do not apply more than 56 fluid ounces/acre per season. 17. cyflufenamid 3.4 fluid 3 Do not exceed 0.044 pounds per year (3.4 ounces Safe (Torino) ounces product/acre X 2 applications). 18. fluopyram + 6.0–8.6 fluid 14 days Also provides control of Botrytis bunch rot at highest Safe tebuconazole ounces labeled rate. Do not apply more than 34 fluid ounces/ (Luna Experience) acre per season. 19. extract of Reynoutria 2.0–4.0 quarts 0 (REI = Also provides control of Botrytis bunch rot. Always tank Safe sachalinensis (Regalia) 4 hrs) mix with other fungicides if disease pressure is high. 1.0–4.0 quarts if tank mixed with other fungicides 20. boscalid 4.5 ounces 14 days Also provides control of Botrytis bunch rot. Do not apply Safe (Endura) more than 24 ounces/acre per season. The rate and max number of applications differ if the target pest is Botrytis. 21. benzovindiflupyr 8.6–10.5 fluid 21 days Spray intervals are 14–21 days. Season total maximum Unknown (Aprovia) ounces (REI = 12 application is 31.5 fluid ounces/acre. hrs) 22. pyriofenone (Prolivo 4.0–5.0 fluid 0 Spray intervals are 14 days. Season total maximum is Unknown 300SC) ounces 16 fluid ounces. Minimum water volume at 50 gallons. Do not make more than two sequential applications of a U8 fungicide. PREBLOOM (15 inch Shoot Growth) TO BLOOM Powdery 1. azoxystrobin (Abound) 10.0–15.5 fluid 14 Azoxystrobin is phytotoxic to certain apple Safe mildew ounces varieties. Read and follow resistance management recommendations on label. RESISTANCE RECOMMENDATION: Tank mix with a contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 2. trifloxystrobin (Flint) 1.5–2.0 ounces 14 Do not use Flint on juice grapes. RESISTANCE Safe RECOMMENDATION: Tank mix with a contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 3. kresoxim-methyl 3.2–4.8 ounces 14 RESISTANCE RECOMMENDATION: Tank mix with a Safe (Sovran) contact fungicide. Do not make sequential applications of a FRAC 11 fungicide.

36 DISEASE MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Diseases Days to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials PREBLOOM (15 inch Shoot Growth) TO BLOOM (continued) Powdery 4. triflumizole 4.0–8.0 ounces 7 With the higher rates and shorter intervals, it can be Safe mildew (Procure 480SC) used for Botrytis Bunch Rot management. Powdery (continued) mildew applications can start around bloom. 5. myclobutanil 3.0–5.0 ounces 14 Begin application at prebloom (12- to 18-inch canes), Safe (Rally 40WSP) and continue on a 14- to 21-day interval. Use higher rates on susceptible varieties or under heavy disease pressure. Do not apply more than 1.5 pounds (0.6 pound of active ingredient) per acre per year. Place myclobutanil into solution before adding oil. 6. tebuconazole 8.6 fluid 14 Maximum 68.8 ounces per acre per season. Safe (Orius 20AQ) ounces 7. quinoxyfen 3.0–4.0 fluid 21 Apply Quintec before visible symptoms of powdery Safe (Quintec) ounces mildew appear. Do not make more than 5 applications per year. Minimum interval is 14 days. Do not apply more than 6.6 fluid ounces per acre per application or more than 33 fluid ounces per acre per year. 8. pyraclostrobin + 8.0–12.5 14 Begin applications at bud break or prior to onset of Safe boscalid ounces disease. Do not make sequential applications of a (Pristine) fungicide containing a FRAC 11 product. Alternate to a fungicide with a different mode of action (FRAC group). Do not use on juice grapes. RESISTANCE RECOMMENDATION: Tank mix with a contact fungicide. 9. petroleum / mineral / 1–2% 0 (REI = Do not mix oil with sulfur or apply either compound Excessive use paraffinic oil 4 hrs) within 3 weeks of the other. Apply at 10- to 14-day harmful intervals. Not all oils are the same purity or have the same PHI for table grapes. The 1–2% recommended rate is for pure (98%+) active ingredient. 10. micronized flowable See label. no PHI Sulfur has both contact and volatile activity when Excessive use sulfur (Microthiol given (REI applied at temperatures between 68°F and 85°F. When harmful Disperss) = 24 hrs) temperatures are colder, it works as a contact product only. When temperatures are warmer, there is risk of phytoxicity. Some phytotoxic effects on juice grapes. 11. sulfur dust 5.0–10.0 no PHI Begin sulfur applications when shoots are 6 to 8 inches Excessive use (Dusting Sulfur) pounds given (REI long. Make a second application when shoots are 12 to harmful = 24 hrs) 15 inches long, and a third about 14 days later. Repeat at 10- to 14-day intervals to protect new growth. 12. potassium bicarbonate 2.5 pounds 0 (REI = Use in 100 gallons of water. Excessive use (Kaligreen) 4 hrs) harmful 13. metrafenone 10.3–15.4 fluid 14 days Do not make more than 3 applications per season. Safe (Vivando) ounces Do not apply more than 46.2 ounces of product per acre per crop. 14. difenoconazole + 16–20 fluid 14 days Also provides control of Botrytis bunch rot. Do not apply Safe cyprodinil ounces more than 80 ounces per acre of Inspire Super per (Inspire Super) season. Do not apply more than 1.4 pounds of active ingredient per acre of a cyprodinil containing product. Do not treat grapes such as Thompson Seedless and Concord which may be used for purposes other than wine. 15. tetraconazole 3.0–5.0 fluid 14 days Do not apply more than 10 ounces of Mettle per acre Safe (Mettle) ounces per year. 16. tebuconazole + sulfur 1.75–2.5 14 days Do not apply more than 20 pounds of Unicorn per acre Unknown (Unicorn) pounds per crop season. Do not mix Unicorn with other DMI fungicides. Do not make applications less than 7 days apart. Do not use on juice grapes.

37 DISEASE MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Diseases Days to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials PREBLOOM (15 inch Shoot Growth) TO BLOOM (continued) Powdery 17. azoxystrobin + 12–14 fluid 14 Do not apply to Concord and Thompson Seedless Safe mildew difenoconazole ounces grapes. Azoxystrobin is extremely toxic to certain apple (continued) (Quadris Top) varieties. Do not apply more than 56 fluid ounces per acre per season. 18. cyflufenamid 3.4 fluid 3 Do not exceed 0.044 pounds per year (3.4 ounces Safe (Torino) ounces product per acre X 2 applications). 19. fluopyram + 6.0–8.6 fluid 14 days Also provides control of Botrytis bunch rot at highest Safe tebuconazole ounces labeled rate. Do not treat grapes such as Thompson (Luna Experience) Seedless and Concord which may be used for purposes other than wine. Do not apply more than 34 fluid ounces per acre per season. 20. extract of Reynoutria 2.0–4.0 quarts 0 (REI = Also provides control of Botrytis bunch rot. Always tank Safe sachalinensis (Regalia) 4 hrs) mix with other fungicides if disease pressure is high. 1.0–4.0 quarts if tank mixed with other fungicides 21. boscalid 4.5 ounces 14 days Also provides control of Botrytis bunch rot. Do not apply Safe (Endura) more than 24 ounces per acre per season. The rate and max number of applications differ if the target pest is Botrytis. 22. benzovindiflupyr 8.6–10.5 fluid 21 days Spray intervals are 14–21 days. Season total maximum Unknown (Aprovia) ounces (REI = 12 application is 31.5 fluid ounces/acre. hrs) 23. pyriofenone (Prolivo 4.0–5.0 fluid 0 Spray intervals are 14 days. Season total maximum is Unknown 300SC) ounces 16 fluid ounces. Minimum water volume at 50 gallons. Do not make more than two sequential applications of a U8 fungicide. BLOOM TO PEASIZE FRUIT Powdery 1. azoxystrobin 10.0–15.5 fluid 14 Azoxystrobin is phytotoxic to certain apple Safe mildew (Abound) ounces varieties. Read and follow resistance management recommendations on label. RESISTANCE RECOMMENDATION: Tank mix with a contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 2. trifloxystrobin (Flint) 1.5–2.0 ounces 14 Do not use Flint on juice grapes. RESISTANCE Safe RECOMMENDATION: Tank mix with a contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 3. kresoxim-methyl 3.2–4.8 ounces 14 RESISTANCE RECOMMENDATION: Tank mix with a Safe (Sovran) contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 4. triflumizole 4.0–8.0 ounces 7 With the higher rates and shorter intervals, it can be Safe (Procure 480SC) used for Botrytis Bunch Rot management. Powdery mildew applications can start around bloom. 5. myclobutanil 3.0–5.0 ounces 14 Begin application at prebloom (12- to 18-inch canes), Safe (Rally 40WSP) and continue on a 14- to 21-day interval. Use higher rates on susceptible varieties or under heavy disease pressure. Do not apply more than 1.5 pounds (0.6 pound of active ingredient) per acre per year. Place myclobutanil into solution before adding oil. 6. tebuconazole 8.6 fluid 14 Maximum 68.8 ounces per acre per season. Safe (Orius 20AQ) ounces

38 DISEASE MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Diseases Days to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials BLOOM TO PEASIZE FRUIT (continued) Powdery 7. quinoxyfen 3.0–4.0 fluid 21 Apply Quintec before visible symptoms of powdery Safe mildew (Quintec) ounces mildew appear. Do not make more than 5 applications (continued) per year. Minimum interval is 14 days. Do not apply more than 6.6 fluid ounces per acre per application or more than 33 fluid ounces per acre per year. 8. pyraclostrobin + 8.0–12.5 14 Begin applications at bud break or prior to onset of Safe boscalid ounces disease. Do not make sequential applications of a (Pristine) fungicide containing a FRAC 11 product. Alternate to a fungicide with a different mode of action (FRAC group). Do not use on juice grapes. 9. petroleum / mineral / 1–2% 0 (REI = Do not mix oil with sulfur or apply either compound Excessive use paraffinic oil 4 hrs) within 3 weeks of the other. Apply at 10- to 14-day harmful intervals. Not all oils are the same purity or have the same PHI for table grapes. The 1–2% recommended rate is for pure (98%+) active ingredient. 10. micronized flowable See label no PHI Sulfur has both contact and volatile activity when Excessive use sulfur (Microthiol given (REI applied at temperatures between 68°F and 85°F. When harmful Disperss) = 24 hrs) temperatures are colder, it works as a contact product only. When temperatures are warmer, there is risk of phytoxicity. Some phytotoxic effects on juice grapes. 11. sulfur dust 5.0–10.0 no PHI Begin sulfur applications when shoots are 6 to 8 inches Excessive use (Dusting Sulfur) pounds given (REI long. Make a second application when shoots are 12 to harmful = 24 hrs) 15 inches long, and a third about 14 days later. Repeat at 10- to 14-day intervals to protect new growth. 12. potassium 2.5 pounds 0 (REI = Use in 100 gallons of water. Excessive use bicarbonate 4 hrs) harmful (Kaligreen) 13. metrafenone 10.3–15.4 fluid 14 days Do not make more than 3 applications per season. Safe (Vivando) ounces Do not apply more than 46.2 ounces of product per acre per crop. 14. difenoconazole + 16.0–20.0 fluid 14 days Also provides control of Botrytis bunch rot. Do not apply Safe cyprodinil ounces more than 80 ounces per acre of Inspire Super per (Inpsire Super) season. Do not apply more than 1.4 pounds of active ingredient per acre of a cyprodinil containing product. Do not treat grapes such as Thompson Seedless and Concord which may be used for purposes other than wine. 15. tetraconazole 3.0–5.0 fluid 14 days Do not apply more than 10 ounces of Mettle per acre Safe (Mettle) ounces per year. 16. tebuconazole + sulfur 1.75–2.5 14 days Do not apply more than 20 pounds of Unicorn per acre Unknown (Unicorn) pounds per crop season. Do not mix Unicorn with other DMI fungicides. Do not make applications less than 7 days apart. Do not treat grapes such as Thompson Seedless and Concord which may be used for purposes other than wine. 17. azoxystrobin + 12.0–14.0 fluid 14 Do not apply to Concord and Thompson Seedless Safe difenoconazole ounces grapes. Azoxystrobin is extremely toxic to certain apple (Quadris Top) varieties. Do not apply more than 56 fluid ounces per acre per season. 18. cyflufenamid 3.4 fluid 3 Do not exceed 0.044 pounds per year (3.4 ounces Safe (Torino) ounces product per acre X 2 applications).

39 DISEASE MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Diseases Days to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials BLOOM TO PEASIZE FRUIT (continued) Powdery 19. fluopyram + 6.0–8.6 fluid 14 days Also provides control of Botrytis bunch rot at highest Safe mildew tebuconazole ounces labeled rate. Do not treat grapes such as Thompson (continued) (Luna Experience) Seedless and Concord which may be used for purposes other than wine. Do not apply more than 34 fluid ounces per acre per season. 20. extract of Reynoutria 2.0–4.0 quarts 0 (REI = Also provides control of Botrytis bunch rot. Always tank Safe sachalinensis (Regalia) 4 hrs) mix with other fungicides if disease pressure is high. 1.0–4.0 quarts if tank mixed with other fungicides 21. boscalid 4.5 ounces 14 days Also provides control of Botrytis bunch rot. Do not apply Safe (Endura) more than 24 ounces per acre per season. The rate and max number of applications differ if the target pest is Botrytis. 22. benzovindiflupyr 8.6–10.5 fluid 21 days Spray intervals are 14–21 days. Season total maximum Unknown (Aprovia) ounces (REI = 12 application is 31.5 fluid ounces/acre. hrs) 23. pyriofenone (Prolivo 4.0–5.0 fluid 0 Spray intervals are 14 days. Season total maximum is Unknown 300SC) ounces 16 fluid ounces. Minimum water volume at 50 gallons. Do not make more than two sequential applications of a U8 fungicide. Botrytis 1. iprodione 1.5–2.0 pints 7 Apply early to mid-bloom. Do not apply after bunch Safe bunch rot (Rovral) closure. Do not make more than four applications per season for wine and sherry grapes; do not make more than one application per season for table and raisin grapes. 2. cyprodinil 10.0 ounces 7 Do not apply more than 30 ounces per acre per crop Safe (Vangard WG) per year. (alone) 3. fenhexamid 1.0 pound 0 Safe (Elevate (REI = 12 50WDG) hrs) 4. pyrimethanil 18.0 fluid 7 Safe (Scala SC) ounces 5. cyprodinil 5.0–10.0 7 Do not apply more than 30 ounces per acre per crop Safe (Vangard WG) ounces per year. (tank mixes) 6. difenoconazole + 16.0–20.0 fluid 14 days Also provides control of powdery mildew. Do not apply Safe cyprodinil ounces more than 80 ounces per acre of Inspire Super per (Inspire Super) season. Do not apply more than 1.4 pounds of active ingredient per acre of a cyprodinil containing product. Do not treat grapes such as Thompson Seedless and Concord which may be used for purposes other than wine. 7. boscalid 8.0 ounces 14 days Also controls powdery mildew. Do not use more than Safe (Endura) 24 ounces per acre per season. 8. fluopyram + 6.0–8.6 fluid 14 days Also provides control of powdery mildew. Do not treat Safe tebuconazole ounces grapes such as Thompson Seedless and Concord which (Luna Experience) may be used for purposes other than wine. Do not apply more than 34 fluid ounces per acre per season. 9. extract of Reynoutria 2.0–4.0 quarts 0 (REI = Also provides control of powdery mildew. Always tank mix Safe sachalinensis (Regalia) 4 hrs) with other fungicides if disease pressure is high.

40 DISEASE MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Diseases Days to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials PEASIZE FRUIT TO VÉRAISON Powdery 1. azoxystrobin 10.0–15.5 fluid 14 Azoxystrobin is phytotoxic to certain apple Safe mildew (Abound) ounces varieties. Read and follow resistance management recommendations on label. RESISTANCE RECOMMENDATION: Tank mix with a contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 2. trifloxystrobin (Flint) 1.5–2.0 ounces 14 Do not use Flint on juice grapes. RESISTANCE Safe RECOMMENDATION: Tank mix with a contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 3. kresoxim-methyl 3.2–4.8 ounces 14 RESISTANCE RECOMMENDATION: Tank mix with a Safe (Sovran) contact fungicide. Do not make sequential applications of a FRAC 11 fungicide. 4. triflumizole 4.0–8.0 ounces 7 With the higher rates and shorter intervals, it can be Safe (Procure 480SC) used for Botrytis Bunch Rot management. Powdery mildew applications can start around bloom. 5. myclobutanil 3.0–5.0 ounces 14 Begin application at prebloom (12- to 18-inch canes), Safe (Rally 40WSP) and continue on a 14- to 21-day interval. Use higher rates on susceptible varieties or under heavy disease pressure. Do not apply more than 1.5 pounds (0.6 pound of active ingredient) per acre per year. Place myclobutanil into solution before adding oil. 6. tebuconazole 8.6 fluid 14 Maximum 68.8 ounces per acre per season. Safe (Orius 20AQ) ounces 7. quinoxyfen 3.0–4.0 fluid 14 Apply Quintec before visible symptoms of powdery Safe (Quintec) ounces mildew appear. Do not make more than 5 applications per year. Minimum interval is 14 days. Do not apply more than 6.6 fluid ounces per acre per application or more than 33 fluid ounces per acre per year. 8. pyraclostrobin + 8.0–12.5 14 Begin applications at bud break or prior to onset of Safe boscalid ounces disease. Do not make sequential applications of a (Pristine) fungicide containing a FRAC 11 product. Alternate to a fungicide with a different mode of action (FRAC group). Do not use on juice grapes. 9. petroleum / white / 1–2% 0 (REI = Do not mix oil with sulfur or apply either compound Excessive use paraffinic oil 4 hrs) within 3 weeks of the other. Apply at 10- to 14-day harmful intervals. Not all oils are the same purity or have the same PHI for table grapes. The 1–2% recommended rate is for pure (98%+) active ingredient. 10. micronized flowable See label no PHI Sulfur has both contact and volatile activity when Excessive use sulfur (Microthiol given (REI applied at temperatures between 68°F and 85°F. When harmful Disperss) = 24 hrs) temperatures are colder, it works as a contact product only. When temperatures are warmer, there is risk of phytoxicity. Some phytotoxic effects on juice grapes. 11. sulfur dust 5.0–10.0 no PHI Begin sulfur applications when shoots are 6 to 8 inches Excessive use (Dusting Sulfur) pounds given (REI long. Make a second application when shoots are 12 to harmful = 24 hrs) 15 inches long, and a third about 14 days later. Repeat at 10- to 14-day intervals to protect new growth. 12. potassium 2.5 pounds 0 (REI = Use in 100 gallons of water. Excessive use bicarbonate 4 hrs) harmful (Kaligreen) 13. metrafenone 10.3–15.4 fluid 14 days Do not make more than three applications per season. Safe (Vivando) ounces Do not apply more than 46.2 ounces of product per acre per crop.

41 DISEASE MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Diseases Days to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials PEASIZE FRUIT TO VÉRAISON (continued) Powdery 14. difenoconazole + 16.0–20.0 fluid 14 days Also provides control of Botrytis bunch rot. Do not apply Safe mildew cyprodinil ounces more than 80 ounces per acre of Inspire Super per (continued) (Inspire Super) season. Do not apply more than 1.4 pounds of active ingredient per acre of a cyprodinil containing product. Do not treat grapes such as Thompson Seedless and Concord which may be used for purposes other than wine. 15. tetraconazole 3.0–5.0 fluid 14 days Do not apply more than 10 ounces of Mettle per acre Safe (Mettle) ounces per year. 16. tebuconazole + sulfur 1.75–2.5 14 days Do not apply more than 20 pounds of Unicorn per acre Unknown (Unicorn) pounds per crop season. Do not mix Unicorn with other DMI fungicides. Do not make applications less than 7 days apart. Do not treat grapes such as Thompson Seedless and Concord which may be used for purposes other than wine. 17. azoxystrobin + 12.0–14.0 fluid 14 Do not apply to Concord and Thompson Seedless Safe difenoconazole ounces grapes. Azoxystrobin is extremely toxic to certain apple (Quadris Top) varieties. Do not apply more than 56 fluid ounces per acre per season. 18. cyflufenamid 3.4 fluid 3 Do not exceed 0.044 pounds per year (3.4 ounces Safe (Torino) ounces product per acre X 2 applications). 19. fluopyram + 6.0–8.6 fluid 14 days Also provides control of Botrytis bunch rot at highest Safe tebuconazole ounces labeled rate. Do not treat grapes such as Thompson (Luna Experience) Seedless and Concord which may be used for purposes other than wine. Do not apply more than 34 fluid ounces per acre per season. 20. extract of Reynoutria 2.0–4.0 quarts 0 (REI = Also provides control of Botrytis bunch rot. Always tank Safe sachalinensis (Regalia) 4 hrs) mix with other fungicides if disease pressure is high. 1.0–4.0 quarts if tank mixed with other fungicides 21. boscalid 4.5 ounces 14 days Also provides control of Botrytis bunch rot. Do not apply Safe (Endura) more than 24 ounces per acre per season. The rate and max number of applications differ if the target pest is Botrytis. 22. benzovindiflupyr 8.6–10.5 fluid 21 days Spray intervals are 14–21 days. Season total maximum Unknown (Aprovia) ounces (REI = 12 application is 31.5 fluid ounces/acre. hrs) 23. pyriofenone 4.0–5.0 fluid 0 Spray intervals are 14 days. Season total maximum is Unknown (Prolivo 300SC) ounces 16 fluid ounces. Minimum water volume at 50 gallons. Do not make more than two sequential applications of a U8 fungicide. Botrytis 1. iprodione 1.5–2.0 pints 7 Apply at beginning of fruit ripening. Do not make Safe bunch rot (Rovral) more than four applications per season for wine and sherry grapes; do not make more than one application per season for table and raisin grapes. 2. cyprodinil (Vangard 10.0 ounces 7 Do not apply more than 30 ounces per acre per crop Safe WG) (alone) per year. 3. fenhexamid 1.0 pound 0 (REI = Safe (Elevate 50WDG) 12 hrs) 4. pyrimethanil 18.0 fluid 7 Safe (Scala SC) ounces

42 DISEASE MANAGEMENT PROGRAM FOR GRAPEVINES

Material per Acre Treated Min. Diseases Days to be Materials & Formulated Before Effect on Controlled Formulation Material Harvest Remarks Beneficials PEASIZE FRUIT TO VÉRAISON (continued) Botrytis 5. cyprodinil 5.0–10.0 7 Do not apply more than 30 ounces per acre per crop Safe bunch rot (Vangard WG) ounces per year. (continued) (tank mixes) 6. difenoconazole + 16.0–20.0 fluid 14 days Also provides control of powdery mildew. Do not apply Safe cyprodinil ounces more than 80 ounces per acre of Inspire Super per (Inspire Super) season. Do not apply more than 1.4 pounds of active ingredient per acre of a cyprodinil containing product. Do not use on juice grapes. 7. boscalid 8.0 ounces 14 days Also controls powdery mildew. Do not use more than Safe (Endura) 24 ounces per acre per season. 8. fluopyram + 6.0–8.6 fluid 14 days Also provides control of powdery mildew. Do not treat Safe tebuconazole ounces grapes such as Thompson Seedless and Concord which (Luna Experience) may be used for purposes other than wine. Do not apply more than 34 fluid ounces per acre per season. 9. extract of Reynoutria 2.0–4.0 quarts 0 (REI = Also provides control of powdery mildew. Always tank mix Safe sachalinensis (Regalia) 4 hrs) with other fungicides if disease pressure is high. VÉRAISON TO PREHARVEST Botrytis 1. iprodione 1.5–2.0 7 Apply prior to harvest as needed. Do not make more Safe bunch rot (Rovral) pounds than four applications per season for wine and sherry grapes; do not make more than one application per season for table and raisin grapes. 2. cyprodinil 10.0 ounces 7 Do not apply more than 30 ounces per acre per crop Safe (Vangard WG) per year. (alone) 3. fenhexamid 1.0 pound 0 Safe (Elevate 50WDG) (REI = 12 hrs) 4. cyprodinil 5.0–10.0 7 Do not apply more than 30 ounces per acre per crop Safe (Vangard WG) ounces per year. (tank mixes) 5. pyrimethanil 18.0 fluid 7 Safe (Scala SC) ounces 6. boscalid (Endura) 8.0 ounces 14 days Do not use more than 24 ounces per acre per season. Safe 7. fluopyram + 6.0–8.6 fluid 14 days Also provides control of powdery mildew. Do not treat Safe tebuconazole ounces grapes such as Thompson Seedless and Concord which (Luna Experience) may be used for purposes other than wine. Do not apply more than 34 fluid ounces per acre per season. 8. extract of Reynoutria 2.0–4.0 quarts 0 (REI = Also provides control of powdery mildew. Always tank mix Safe sachalinensis (Regalia) 4 hrs) with other fungicides if disease pressure is high.

43 VIRUSES OF GRAPEVINES

Like any other crop, grapevines are susceptible to Since all debilitating virus diseases are spread a broad range of plant viruses. In fact, grapevines through grafting, the first and foremost approach appear to be infected with more viruses than any in this direction should be planting virus-tested other perennial woody species. Viruses infecting materials obtained from reliable and certified grapevines are diverse, with distinct biological sources. Due to the distinct nature of viruses and properties and genome characteristics. Some of their diverse modes of spread, there is no “one- these viruses are widely distributed wherever size fits-all” approach for the management of viral grapevines are grown, and others are present diseases. Thus, accurate diagnosis of viruses is the locally or in limited geographic range. Many of cornerstone of virus disease management strate- these viruses are spread by aerial transmission gies. Constant vigilance and careful monitoring through insect vectors and some are spread for any unusual symptoms will facilitate quick through soil by nematodes. action before the problem gets out of control. A comprehensive virus indexing of plant materi- With no exception, all viruses infecting grapevines als should be done to reduce spread of infection are transmissible through grafting. Since grape- in existing vineyards, because field diagnosis of vines are propagated through vegetative cuttings grapevine diseases may be difficult and symp- to maintain clonal identity or trueness-to-type, the toms displayed in the field may often be confused risk of spreading viruses to new areas is far greater with other problems, such as abiotic stress (viz. through the distribution of cuttings from infected nutrient deficiency, herbicide damage), physical vines than by other modes of virus dissemination. damage, and genetic abnormalities. In addition, In general, virus diseases affect growth and lon- expression of many viral symptoms depends on gevity of grapevines, as well as yield and quality several variables including cultivar, age of vine attributes of grapes, leading to economic losses at which infection occurred, particular stage of to growers. Poor quality grapes, in turn, lead to disease development, and time of year when the a marked decline in producing premium wines. symptoms were observed. Many different types of As the demand for premium wines is increasing diagnostic tests are available to confirm the pres- globally, it is critical to maintain healthy vines for ence of a particular virus. They include biological producing “healthy” wines. indexing (field indexing and mechanical inocu- lation on to herbaceous hosts), serological tests Among the virus diseases infecting grapevines, (enzyme-linked immunosorbent assay or ELISA), “traditional” virus diseases such as Grapevine and molecular tests (polymerase chain reaction or leafroll disease, ruguose wood complex, and PCR). These are complementary and so a combi- Grapevine fanleaf disease are of great economic nation of tests can be used to confirm the pres- significance globally and countries around the ence of a virus in suspected plant material. world. However, many of these diseases are complex syndromes and are still largely unsolved virus disease problems. Fortunately, vineyards in Wash- Grapevine Leafroll Disease ington State are free from many, though not all, of the debilitating virus diseases. Grapevine leafroll disease (GLRD) is a complex viral disease of major concern in Washington NOTE: State regulations prohibit the importation State. It is estimated that GLRD currently affects of grapevines that are not certified as virus-free. about 10-15% of the acreage of wine and juice grapes combined. In recent years, however, the spread of GLRD has been increasing through- Management of Grapevine Virus out the state. In fact, GLRD is currently consid- Diseases ered the biggest constraint to the production of premium grapes for high quality wines in Once a virus disease is established in a given Washington State. Significant reduction in yield vineyard, it is not amenable to any curative or is commonly reported due to GLRD, with fewer therapeutic control measures. Given the difficul- and smaller bunches. In addition, fruit maturity ties in achieving high levels of preventive measures is delayed by 3 weeks to 1 month depending on and the cost of replacing infected vines, it is vital severity of symptoms, cultivar and environmental to focus efforts on eliminating or reducing initial conditions. GLRD affects the quality of grapes by sources of infection. delaying the accumulation of sugars, lowering the

44 accumulation of anthocyanins, and causing up ditions. Studies conducted outside the U.S. have to 50% loss of pigment concentration in red wine shown that GLRaV-3, in the presence of mealy- varieties. GLRD is, therefore, a particularly serious bugs as vectors, can spread from a low incidence problem for red wines. to almost complete infection of a new vineyard in less than a decade. Thus, grape mealybugs are an GLRD do not produce symptoms for most of the increasing concern for Washington grape growers, season—these begin to appear in the early part primarily due to the fact that they are vectors of of the Fall. GLRD symptoms are more dramatic GLRD. For more details on GLRD, please see Grape- in red- and black-fruited cultivars than white- vine Leafroll Disease (EB2027E). A disease manage- fruited cultivars. In the former cultivars, the foliar ment strategy for controlling GLRD should involve symptoms are characterized initially by red and planting tested-virus free vines and Mealybug/scale reddish-purple tints in the inter-veinal areas. These insect-free planting materials, close monitoring of discolorations may coalesce with time, leading to the vineyards for mealybugs and scale insects and reddish-purple color of inter-veinal areas and green their control by judicious use of pesticides, and tissue near the main veins. In the advanced stages, sanitation in terms of replacing infected vines with the margins of infected leaves roll downward, tested-virus free vines during formative years of expressing the symptom that gives the disease its vineyard establishment. common name. Thus, the major symptom in late Fall is red leaves with green veins and downward- rolled leaf margins. In the white-fruited cultivars, Rugose Wood Complex (Grafted Vines) infected leaves turn yellow between the veins and show rolling. GLRD symptoms develop during the All the graft-transmitted disorders of the woody late summer to autumn period in these cultivars trunk are grouped under Rugose Wood (RW) and vary depending on the cultivar and time of disease complex. RW is characterized by modifica- the year. Usually, the symptoms begin toappear on tions of the woody cylinder, typified by marking the mature leaves near the base of the shoots and with pits and/or grooves. It consists of four differ- develop progressively up the canes. ent disorders, namely rupestris stem pitting (RSP), Kober stem grooving, LN33 stem grooving, and The GLRD is a complex disease. Several corky bark. They may occur on the scion, root- serologically distinct viruses, termed Grapevine stock, or both, depending on the rootstock and leafroll-associated viruses (GLRaVs), and numbered scion cultivar. European Vitis vinifera cultivars carry sequentially GLRaV-1, -2, -3, etc., have been symptomless infections of RW complex until they associated with the disease. However, GLRaV-8 are grafted onto American rootstocks. Thus, in is no more considered as one of the GLRaVs. eastern Washington where grapevines are grown as own-rooted vines, symptoms induced by the four Recent studies have shown that GLRaV-1, -2, -3, disorders of RW complex may not be apparent. and -4 and its strains GLRaV-5 and GLRaV-9 are present in Washington State vineyards. Other Infections due to RW complex can significantly GLRaVs have not been documented so far in reduce the survival rate of grafted vines when com- Washington vineyards. GLRaV particles are highly pared to grafted virus-tested vines. Moreover, the flexuous and localized in the vascular tissue, i.e. severity of disease may vary according to the geno- phloem. Consequently, these viruses possibly type of the rootstock that is grafted with infected interfere with the movement of nutrients in the scion wood. RW affected vines may be dwarfed and vine, thereby causing secondary biochemical less vigorous than normal and may have delayed and physiological effects that could lead to the bud opening in the spring. Some vines decline development of foliar symptoms. Since 1989, and may die within a few years after planting, due plant-to-plant spread of GLRD has been observed to graft incompatibility. In western Washington, in vineyards in various countries and insect vec- grapevine cultivars are propagated by grafting onto tors such as mealybugs (Pseudococcidae) and scale suitable rootstocks to gain security from phylloxera insects (Coccidae) are thought to be responsible. and nematode-borne virus infection, and to pro- At least six different mealybug species have been mote early ripening in areas of reduced heat units. documented on grapevines in California. How- In the Columbia River valley of eastern Washing- ever, only grape mealybug (Pseudococcus mariti- ton, there is an increased tendency to top-work mus) is known to occur in Washington vineyards. existing grapevines to other cultivars in order to Grape mealybug has been shown to be capable save time and costs in establishing new vineyards. of transmitting GLRaV-3 under laboratory con- Because RW is symptomless in V. vinifera, graft-

45 ing onto untested vines can unwittingly result in by far the more efficient vector. Grapevine decline infection of the new scion. is another nematode-transmitted virus disease. At least three distinct viruses—Tomato ring spot virus The etiology of RW syndrome is complex and has (TomRSV), Tobacco ring spot virus (TRSV), and not yet been completely worked out. At least four Peach rosette mosaic virus—have been implicated different viruses—namely, Grapevine Virus A (GVA), in the genesis of the disease. Two distinct strains B, D and E, and Grapevine rupestris stem pitting- of TomRSV are present and they induce different associated virus (GRSPaV)—have been consistently symptoms. GFLV and TRSV have recently been found in different disorders of RW complex. How- documented in Washington State vineyards. ever, none of these viruses has been identified or confirmed as the causal agent of RW complex. All In contrast, management of soil-borne diseases like these viruses are filamentous, phloem-limited, and Grapevine fanleaf disease involves testing the soil are graft-transmissible, and thus all four disorders for nematode vectors before planting a vineyard, are spread by infected propagation material. Corky soil fumigation if any nematode vectors are present bark disease is also transmitted by mealybugs. The and planting virus-tested planting materials. Soil natural spread of rupestris stem pitting and stem treatment to control nematode vectors may not grooving diseases is not yet established. Currently, provide lasting control in the existing vineyards. GRSPaV is known to be present in Washington The only certain control will be to remove the State and according to some estimations, it affects vineyard and fallow the ground for six to ten years, approximately 5% of the grapevines in the state. so that both the residual roots from the old vine- When GRSPaV is present alone, grapevines do not yard and the vector nematode population die out. produce foliar symptoms and there are no effects Initial investments in testing the soil for nematode on the growth and yield of plants. However, when vectors and planting virus-tested cuttings are pref- present as mixed infections with other viruses, erable to such measures, and will help maintain a RW-type symptoms may occur. Currently, GRSPaV healthy vineyard. is not listed as a restricted virus in certification schemes in other states like California, whereas it is a controlled virus in the Washington State certifica- Grapevine Red Blotch Disease tion program. Therefore, it is important to import planting material tested for GRSPaV. GVA, GVB Recent studies by next-generation sequencing tech- and GVE have so far been documented in Wash- nologies have reported the presence of a new virus, ington State vineyards. However, GVA and GVB tentatively designated as Grapevine red blotch- appear to be more widespread than GVE. associated virus (GRBaV), with single-stranded DNA as its genome. This virus is implicated in symptoms of the Grapevine red blotch disease Grapevine Fanleaf and Grapevine (GRBD). Grapevine red blotch disease has been Decline Diseases documented recently in certain Vitis vinifera cultivars planted in Washington. In red-fruited culti- Grapevine fanleaf is a soil-borne disease spread vars, mature leaves at the bottom portions of canes by nematodes with a world-wide distribution. show red veins, red blotches and total reddening. The disease often occurs in patches in the vine- No such symptoms are apparent in white-fruited yard. In fact, it is the oldest known virus disease cultivars. In red-fruited cultivars, GRBD-affected of Vitis vinifera. All grape species and cultivars are vines show poor growth with significant reduction susceptible to fanleaf disease. Infection due to in fruit yield and berry quality. fanleaf leads to vine decline but not death of the vine. Like other diseases, fanleaf disease drastically The role of GRBaV in producing symptoms of affects vine growth and yield and quality of grapes. GRBD is not fully understood. It should be noted, The diseased vines show three distinct types of leaf however, that symptoms produced by GRBD show symptoms: fanleaf deformation, yellow mosaic, several similarities with symptoms of GLRD. Fur- and vein banding. All of these symptom patterns ther studies are in progress to better understand are caused by the same virus and reflect varied epidemiological differences between these two responses by different cultivars. Fanleaf is caused distinct diseases in Washington vineyards. In the by Grapevine fanleaf virus (GFLV). The two known meantime, growers are advised to test suspected nematode vectors are Xiphinema index and X. samples for accurate identification of viruses asso- italiae. Xiphinema index, or dagger nematode, is ciated with GRBD and GLRD.

46 Potential Virus Diseases viroids (Hop stunt viroid, Grapevine yellow speckle viroid-1 and Grapevine yellow speckle viroid-2) have There are many other diseases reported from dif- also been documented in the state vineyards. ferent countries and they are of local or minor sig- Although other virus and virus-like problems are nificance. With rapid expansion of plantings and not yet reported in Washington State vineyards, changing viticultural practices, new and emerging constant vigil and careful monitoring of vineyards problems with elusive virological etiology have is important to make sure that no new virus disease become increasingly apparent in several grape- growing countries, such as virus-induced graft becomes established in the state. It is very impor- incompatibility disorders, destructive phytoplasma tant that vines showing any unusual symptoms be epidemics, and viroid-induced diseases. Grapevine brought to the attention of the Grape Virologist fleck virus and Grapevine syrah virus-1 have recently (Naidu Rayapati, [email protected]) at WSU- been documented in Washington vineyards. Three IAREC, in Prosser.

47 SPRAY RECOMMENDATIONS

General WP formulations, but are much more likely to injure fruit and foliage. • The rates given per acre and amount of formulated material in the tables are based Dry Flowable (DF) formulations are similar to on dilute sprays applied by ground equip- wettable powders except that the powders (clay ment. You generally need approximately the particles) are formed into tiny spheres. They do not same amount of active ingredients of insec- tend to pack together, so they “flow” easily from ticides, fungicides, or growth regulators per the product container. Another name used for this acre whether you apply them in dilute form, type of formulation is Water Dispersible Granule. as concentrates, or as semiconcentrates. Flowable (F) formulations are a liquid and vis- • Proper pruning and spacing of vines is an aid cous concentrate of suspendible pesticide in water. in the control of many insects and diseases. They usually cause less injury to fruit and foli- • Proper timing of sprays and adequate cov- age than EC formulations and generally, but not erage is essential for good pest and disease always, are as safe as WP formulations. control. Each vineyard operation differs with regard to equipment, spacing, and size of Soluble powders (SP) are powder formulations vines, local weather conditions, and particu- that dissolve in water. A few pesticides and many lar pest problems. The timing, concentration, fertilizers are prepared as soluble powders. and gallonage of spray per acre should vary accordingly. Dusts (D) are usually made by mixing the chemical toxicant with finely ground talc, clay, or dried • Because of the differences between districts, plant materials. Because of extreme drift hazards, vineyards, and even parts of the same dusts are now seldom used in vineyards. vineyard, detailed spray programs should be worked out for your vineyard(s). Consult Granules (G) are formed by saturating an inert your county Extension agent or field carrier with pesticide. The particles are 30 to 60 representative. mesh size. Granules are usually used for soil- or • Where wettable sulfur is recommended, any water-dwelling pests. formulation of finely ground sulfur paste Baits consist of a poison plus a substance which having at least 60% sulfur may be substituted will attract the pest. In vineyards, they are used at the rate of 1 pint of sulfur paste in place of only in cover crops and around vines. They are 1 pint of wettable sulfur. less hazardous to the general environment than many sprays and dusts. Birds, however, do occa- Formulations sionally feed on baits and may die if they eat large amounts. Wettable powders (WP) are dry forms of pesticides. The toxicant is mixed with special powders, Calibration of Vineyard Sprayers and wetting agents are added to make the mixture blend readily with water. Wettable powders form The following steps are suggested in properly a suspension-type spray, which must be kept agi- calibrating an air-blast sprayer: tated in the spray tank. This type of formulation is often recommended for use in grapes because it is • Determine by trial the rate of travel that will less likely to cause foliage injury. allow the air-blast to distribute the spray throughout the vines. This should be about Liquid concentrates (L or LC) are formulations 2 to 2.5 miles per hour, and never under containing toxicants which are water soluble. No 0.5 mile per hour or over 3 miles per hour. emulsifying agents or organic solvents are required. Direct most of the air toward the thick- The designations L and LC are sometimes used to est and most distant parts of the vines and indicate emulsifiable concentrates. less toward the edges. Turn upper and lower nozzles off if spray from those nozzles is Emulsifiable concentrates (EC)contain a pesti- not aimed directly into the canopy. Some cide and an emulsifying agent in a suitable solvent. machines have vanes or movable air outlets These materials are diluted with water and applied that can be adjusted to help direct the air as sprays. They leave much less visible residue than where it is needed.

48 Speedometers on tractors are not always representative will be able to give you advice on accurate. Ensure their accuracy by using the nozzle arrangement and size. vine spacing-miles per hour chart or use a hiking gps. An example of the vine spacing method is assume your vine spacing is Dilutions 8 feet and you pass 11 vine spaces (88 feet) in 1 minute, you are traveling at 1 mile per Low-Volume Spraying. There are various defini- hour. A watch with a sweep second hand will tions for low-volume sprays. The generally accepted be very helpful in determining your speed. gallonages for spray work in vineyards include: Further calculations are shown in Table 1. Dilute (High Gallonage)—301 or more gallons • Decide on the specific gallonage to be per acre applied per acre. Use 75 gallons for our Semi-Concentrate—101 to 300 gallons per acre example. Concentrate—10 to 100 gallons per acre • Now set up the sprayer to apply the needed Very Low Volume—1 to 9 gallons per acre gallonage at the desired speed. Use the following formula to determine the discharge Ultra Low Volume—Less than 1 gallon per acre rate from the manifold: undiluted material.

gallons per acre x mph x feet between rows Many ground sprayers using concentrate sprays apply 50 to 100 gallons of spray per acre. Others, 1,000 however, may apply as little as 10 gallons per acre. = gallons per min. (1 side) Information on use of much of this equipment on grapes in eastern Washington is not known at Using the predetermined gallonage and speed in present. The tables showing acreage rates in this the example: publication may be used as general guide in applying low-volume sprays. Check with your field rep- 75 x 1 x 8 resentative or processor, however, before applying = 0.6 gallons per minute 1,000 low-volume sprays. They may not be permitted by label directions. Set the total output from all the nozzles on each Where oil-susceptible varieties or young vines are side of the manifold to apply 0.6 gallons per to be sprayed, lower rates than those shown in minute. the table for horticultural mineral oil and oil- The size and arrangement of the nozzles is very phosphate mixes may be desirable. Information important and will determine whether or not the in Washington on oil rates for total gallonages sprayer will give satisfactory pest control. Be sure below 60 gallons per acre have not been studied. the greatest amount of spray is applied through Be sure that agitation is adequate to keep the the center and upper portion of the vines. spray mixed uniformly while applying oils and oil-phosphate mixes at all gallonages, but be Your equipment dealer has charts showing the particularly careful at low-volume or concen- output of various nozzle sizes. Both dealer and field trate rates.

Table 10. Vine spaces per minute. Vine spacing in a row 6 ft 7 ft 8 ft 9 ft 10 ft Miles/hour Feet/minute Number of Vines 1.0 88 14.7 12.8 11.0 9.8 8.8 1.5 132 22.0 18.9 16.5 14.7 13.2 2.0 176 29.3 25.1 22.0 19.6 17.6 2.5 220 36.7 31.4 27.5 24.4 22.0 3.0 264 44.0 37.7 33.0 29.3 26.4 4.0 352 58.8 50.2 44.0 39.2 35.2

49 1 gallon 0.8 oz (23 g) 0.32 oz (9 g) 0.16 oz (5 g) 0.08 oz (2 g) 6 oz (189 ml) 5 oz (151 ml) 4 oz (113 ml) 0.64 oz (18 g) 0.48 oz (14 g) 1 oz (38 ml, 2 tbl) 0.2 oz (5 ml, 1 tsp) 2.5 oz (76 ml, 5 tbl) 0.3 oz (9.5 ml, 2 tsp) 3 gallons 2.4 oz (68 g) 1.9 oz (54 g) 1.4 oz (41 g) 1.0 oz (27 g) 0.5 oz (14 g) 0.25 oz (7 g) 8 oz (227 ml) 4 oz (114 ml) 19 oz (568 ml) 15 oz (454 ml) 12 oz (341 ml) 1 oz (28 ml, 2 tbl) 0.5 oz (14 ml, 1 tbl) 5 gallons 2 oz (47 ml) 1 oz (24 ml) 4 oz (113 g) 3.2 oz (91 g) 2.4 oz (68 g) 1.6 oz (45 g) 0.8 oz (23 g) 0.4 oz (11 g) 6 oz (189 ml) 32 oz (946 ml) 19 oz (568 ml) 13 oz (379 ml) 26 oz (757 ml) 0.5 gal 10 gallons 3 oz (95 ml) 8 oz (227 g) 3.2 oz (91 g) 1.6 oz (45 g) 0.8 oz (23 g) 1.6 oz (47 ml) 6.4 oz (181 g) 4.8 oz (136 g) 26 oz (757 ml) 13 oz (379 ml) 51 oz (1514 ml) 38 oz (1136 ml) 2 lb 1 lb 2 gal 1 gal 2.5 lb 1.5 lb 0.5 lb 2.5 gal 1.5 gal 0.5 gal Quantities of material for indicated quantities water 50 gallons 4 oz (113 g) 8 oz (237 ml) 16 oz (473 ml) 3 lb 3 gal 1.5 lb 1.5 gal 3.75 lb 2.25 lb 3.75 gal 2.25 gal 0.75 gal 75 gallons 6 oz (170 g) 12 oz (340 g) 24 oz (710 ml) 12 oz (355 ml) 5 lb 4 lb 3 lb 2 lb 1 lb 5 gal 4 gal 3 gal 2 gal 1 gal 0.5 lb 1 qt (32 oz) 1 pt (16 oz) 100 gallons 1 Type of Type material For wettable powders, the number of dry tablespoons per ounce of dry pesticide varies greatly with different products because some materials are light and Dry: Wettable Dry: Wettable Powder Liquid: Emulsifiable concentrate gal = gallons, lb pounds, oz ounces, g grams, qt quart, pt pints, tbl tablespoons, tsp teaspoons 1 In general, there are 2 to 6 level tablespoons per ounce of these dry materials. It is always better to weigh your materials than use fluffy; others compact and heavy. weigh out the appropriate amount and then if you want to convert ounces tablespoons for small amounts of materials used repeatedly, tablespoons. However, empirically measure the tablespoons or teaspoons. Table 11. Dilutions for wettable powder and emulsifiable concentrates. and emulsifiable powder 11. Dilutions for wettable Table

50 REGULATORY INFORMATION

Federal and state pesticide regulations change or lessee of the treated field to see that workers frequently. Growers are advised to check with comply with the standards. county agents or pest control consultants for the latest information before applying any With any pesticide, unprotected persons must not chemical. Growers are also advised to check be allowed in areas being treated, and employees, with their buyers, processors, or packers before other than those involved in the application, must applying chemicals. In some cases, buyers and not be exposed to drift. processors may not accept grapes treated with certain materials, even though these materials are approved for use by federal and state agencies. Licensing Most licenses must be renewed annually. Any per- Pesticide Residues on Grapes son licensed as an applicator or operator is quali- fied as a certified applicator for the use of restrict- Residues of pesticides are permitted on harvested ed-use pesticides. Those who sell, distribute, apply crops only under two conditions: an exemption is or advise on the use of pesticides may need to be granted to the requirement for a tolerance, or the licensed by the Washington State Department of residue level does not exceed tolerances established Agriculture (WSDA), Pesticide Management Divi- by the Environmental Protection Agency. sion, in one or more of the following categories.

To avoid illegal residues, it is imperative that you Commercial Applicator. Any individual apply- follow directions carefully with respect to rates of ing pesticides for hire to the lands of another must application, number of applications, and intervals obtain an annual license. between application and harvest. You must avoid drift, especially where other crops are adjacent to Pesticide Dealer and Dealer Manager. the crop being treated. Pesticide residues that are Any individual acting as a pesticide dealer must permitted on one crop may be illegal when pres- obtain an annual license from the WSDA. All ent on another. For lists of pesticide tolerances, see pesticide dealer outlets must employ a pesticide the Global MRL database at https://www.globalmrl. Dealer Manager. com/db#login. Pest Control Consultant. Any individual who offers recommendations, technical advice, or aid Pesticide Restricted Entry Standards on the use of pesticides except those packaged only for home and garden use must obtain an annual Unprotected workers must not be permitted in license. They cannot apply pesticides or supervise fields treated with pesticides during a specified applications. interval after application. This interval, known as a restricted entry interval, appears on the label. Private Pesticide Applicator. Any person who All production agricultural pesticides state the applies or supervises the application of restricted- restricted entry interval (REI), and it’s usually in use pesticides on land owned, leased, or rented the “Agricultural Use Requirements” section of by him/her or by an employer for the purpose of the label. producing (growing) an agricultural commodity. Workers may enter treated fields before the end of Unlicensed employees of the Private Applicator the restricted entry period if they wear protective may apply restricted-use pesticides only if super- clothing and if they are trained as “early entry vised by the Private Applicator. Supervision of such workers.” Protective clothing items required for employees includes adequate instruction regarding early entry are stated on the label. the safe and proper application of these pesticides as well as being readily accessible to the employee Warnings must be given to workers who are if problems occur. The Private Applicator bears expected to work in treated fields within 30 days legal responsibility for any pesticide application of the application. Warnings may be given orally, conducted by employees. The supervised employee or by signs at the usual entrances to the field, must be a trained pesticide handler under the and must be written in a language the workers Worker Protection Standard (page 1). A grower understand. It is the responsibility of the owner may apply pesticides on the lands of another on

51 trade-work basis without obtaining a commercial “Information” means telling workers about your applicator’s license. chemical labels and safety data sheets (SDS). SDS are obtained from chemical manufacturers and dealers and kept on file where workers can see Chemigation them. All workers must be told where hazardous chemicals, such as pesticides, are being used. State and federal regulations prohibit application of any pesticide through an irrigation system un- “Training” must be given to workers who are using less the label specifically allows this means of ap- the chemicals or who might be exposed to them. plication. Backflow prevention devices, automatic check valves, and interlocking controls are required For example, a person who enters a field that has on all systems used for chemigation. Any person been treated during the current growing season is calibrating, loading, starting up, monitoring dur- considered to be exposed and therefore must be ing application, or shutting down the system must given the training. be, or be supervised by, a certified applicator. For more information, contact Tom Hoffmann, WSDA, This training includes: 509-766-2574. • How to tell if the chemical is present (what it looks like, what it smells like). The state of Washington has declared certain pesticides to be restricted for the protection of • What the physical and health hazards are groundwater. These may only be used by certified (symptoms or effects of overexposure). applicators. There are two chemicals registered for • How workers can protect themselves (the use on grapes that are restricted for protection of SDS or label should explain the appropriate groundwater: diuron and simazine. protection, such as gloves or a face mask). • Good work practices (no eating or smoking State Laws and Regulations around chemicals; wash thoroughly after leaving the area). Complete state laws and regulations can be • Emergency procedures (whom to call and obtained from the Pesticide Branch, Washington what to do if someone is overexposed). State Department of Agriculture, 2015 South 1st Street, Yakima, WA 98902, (509) 575-2746, or from • Where to find the SDS (make available to the Washington State Department of Agriculture, workers). 1111 Washington Street S.E./2nd floor NRB Build- • How to obtain more information on the ing, P.O. Box 42560, Olympia, WA 98504-2560, toll chemical and how to use that information. free 1-877-301-4555. Pesticide dealers must give farmers SDS with the initial purchase of all restricted-use pesticides. Worker Right-To-Know Act Pesticide applicators who sell pesticides must also provide SDS. The Worker Right-To-Know Act was passed by the Washington State legislature in 1984. It is fairly The Department of Labor and Industries will similar to the federal/state Worker Protection Stan- answer your questions about this program. For dard, but has additional requirements. It requires a copy of the new guidelines, call 360-902-5478. employers to train and inform their employees Both English and Spanish speakers may also about hazardous chemicals in the workplace. The contact Pedro Serrano at 360-902-6652 or email act does not apply to family operated vineyards or [email protected] , or call toll-free within businesses that do not rely on hired workers. The Washington: 1-800-547-8367. For more informa- following statement about the law was provided by tion, visit the Worker Right-to-Know Act website the Department of Labor and Industries: at http://www.lni.wa.gov/safety/topics/atoz/Work- ersRights/default.asp . Grape growers now join all employers statewide in warning the workers about hazardous chemicals. This warning takes the form of information and training. Horticultural Pest and Disease Boards Operators must develop and maintain a written program that explains how they inform and train their Washington counties may establish Horticultural employees about the hazardous chemicals they are Pest and Disease Boards to more effectively control likely to be exposed to. and prevent the spread of horticultural pests and

52 diseases. Boards are located in the following coun- shortly following the application of another ties: Adams, Benton, Franklin, Chelan-Douglas, have been put into three categories by the Grant, Kittitas, Klickitat, Okanogan, Skagit, Spo- Environmental Protection Agency: kane, Walla Walla, Whatcom, and Yakima. The boards may determine which pests and diseases Category 1. The use is indicated on the label of must be controlled, receive complaints concern- one or more EPA-registered products. ing infestation of horticultural pests, inspect any parcel of land to determine the presence of pests, Category 2. The use is covered by state order any landowner to control pests and prevents registration. their spread from the property, or control the pests and charge the landowner for the expense of the Category 3. The use has been tested and control work. recommended by Agricultural Experiment Stations or State Departments of Agriculture, or Boards can be created by presenting a petition is a common agricultural practice. Applications signed by 25 landowners to the county commis- recommended on EPA or State approved labels sioners, or the commissioners can formulate a (Categories 1 and 2) are legal. board on their own initiative, following a public hearing. Members of the board are appointed by Other uses (Category 3) will be permitted if dosages the commissioners, with the horticultural inspec- do not exceed label instructions for any product in tor-at-large for the county involved being a man- the mix used singly for the same pests on the same datory voting member. Operational funds for the crop and if labels do not explicitly instruct against board must be provided by the commissioners. such a mixture.

Complaints are to be submitted to the board in The EPA has not reviewed the effectiveness or the writing. For more information on submitting a human or environmental hazards of combina- complaint, contact your District Horticultural tions of products in Categories 2 and 3. The user is Inspector or your county Extension agent. at risk in applying these mixtures with respect to effects on crops and equipment, applicator safety, Tank Mixes environmental effects, and preharvest tolerance intervals. If a particular mixture causes adverse Tank mixes of two or more pesticides and effects, the EPA will, on a case-by-case basis, rule applications of one pesticide immediately or that it is not permitted.

53 54

Use pesticides with care. Apply them only to plants, animals, or sites listed on the label. When mixing and applying pesticides, follow all label precautions to protect yourself and others around you. It is a violation of the law to disregard label directions. If pesticides are spilled on skin or clothing, remove clothing and wash skin thoroughly. Store pesticides in their original containers and keep them out of the reach of children, pets, and livestock.

WSU Extension bulletins contain material written and produced for public distribution. Alternate formats of our educational materials are available upon request for persons with disabilities. Please contact Washington State University Extension for more information.

You may order copies of this and other publications from WSU Extension, at 1-800-723-1763 or http:// pubs.wsu.edu.

Issued by Washington State University Extension and the U.S. Department of Agriculture in furtherance of the Acts of May 8 and June 30, 1914. Extension programs and policies are consistent with federal and state laws and regulations on nondiscrimination regarding race, sex, religion, age, color, creed, and national or ethnic origin; physical, mental, or sensory disability; marital status or sexual orientation; and status as a Vietnam-era or disabled veteran. Evidence of noncompliance may be reported through your local WSU Extension office. Trade names have been used to simplify information; no endorsement is intended. Revised December 2018. EB0762