Weed Control Recommendations for Christmas Tree Growers (Revised February 2018)
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Weed Control Recommendations for Christmas Tree Growers (Revised February 2018) Contents Herbicide Chemical and Trade Name………................................Page 2 What is "lbs. AIA"? ..................................................................... Page 3 Why Control Weeds .................................................................... Page 4 Levels of Control ........................................................................ Page 4 The Herbicides ............................................................................ Page 5 Postemergence Herbicides ...................................................... Page 5 Preemergence Herbicides .................................................... ….Page 10 Weed Control Program ................................................................ Page 14 Recommendations - Field ............................................................ Page 15 Site Preparation ....................................................................... Page 15 Preventing Weed Growth ........................................................ Page 15 Table 1. Herbicide Combinations ............................................ Page 17 Eliminating Weeds From Existing Plantings ........................... Page 18 Recommendations - Seedbeds ..................................................... Page 19 Site Preparation ....................................................................... Page 19 Preventing Weed Growth ........................................................ Page 19 Eliminating Weeds From Existing Plantings ........................... Page 20 Herbicide Sprayer Calibration……………………………………Page 21 Summary ..................................................................................... Page 22 Chemical Name Trade Name Page Trade Name Chemical Name Page 2,4-D Barrage, HardBall, Aatrex, Atra 5 Atrazine 10 Lo-Vol 4 & 6, Accord Glyphosate 5 LV4, Salvo 10 Arrow Clethodim 8 Atrazine Aatrex, Atra 5 10 Barricade Prodiamine 13 Atrazine Barrage 2,4-D 10 + 2,4-D Shotgun 10 Basagran T/O Bentazon 10 Bentazon Basagran T/O 10 Biathlon Oxyfluorfen + prodiamine 13 Clethodim Arrow, Envoy, Cleo, Cavalcade Prodiamine 13 Intensity, Section, Devrinol Napropamide 11 Element 3 Triclopyr 9 Shadow, Trigger, Endurance Prodiamine 13 Tapout 8 Envoy Clethodim 8 Clopyralid Stinger 9 Fusilade DX & II Fluazifop-p-butyl 8 Dimethenamid-p Tower 14 Gallery Isoxaben 12 Flazasulfuron Mission 13 Galligon Oxyfluorfen 12 Fluazifop-p-butyl Fusilade DX & II 8 Garlon Triclopyr 9 Flumioxazin Broadstar, Sureguard13 Glyfos &Glypro Glyphosate 5 Glyphosate Roundup Pro/Ultra Goal & Goaltender Oxyfluorfen 12 Accord, Glyfos Guardrail Prodiamine 13 Many others 5 HardBall 2,4-D 10 Hexazinone Intensity Clethodim 8 + sulfometuron Westar 14 Kerb Pronamide 14 Indaziflam Marengo, Specticle 13 Lo-Vol 4&6, LV4 2,4-D 10 Isoxaben Gallery 12 Marengo Indaziflam 13 Metolachlor Pennant Magnum 13 Mission Flazasulfuron 13 Napropamide Devrinol 11 Octane 2 Pyraflufen 10 Oryzalin Surflan, Prozalin, OxyStar Oxyfluofen 12 Oryzalin 4 Pro 13 Pennant Magnum Metolachlor 13 Oxadiazon Ronstar, Starfighter 13 Pendulum Pendimethalin 13 Oxyfluorfen Galligan, Goal, Pendulum Aquacap Pendimethalin 13 PreM Pendimethalin 13 Goaltender, OxyStar 12 Princep Simazine 11 Oxyfluorfen ProClipse Prodiamine 13 + oxadiazon Regal 0-0 13 Prozalin Oryzalin 13 Oxyfluorfen + prodiamine Biathlon 13 Regal 0-0 Oxyfluorfen + oxadiazon 13 Pendimethalin AquaCap, Pendulum, Ronstar Oxadiazon 13 PreM 13 Roundup Pro/Ultra Glyphosate 6 Prodiamine Barricade, Cavalcade, Salvo 2,4-D 10 Endurance, Guardrail, Section Clethodim 8 ProClipse 13 Select Clethodim 8 Pronamide Kerb 14 Shotgun Atrazine + 2,4-D 10 Pyraflufen Octane 2 10 Simazat Simazine 10 Sethoxydim Segment 8 Simtrol Simazine 10 Simazine Princep, Simazat, Specticle Indaziflam 13 Simazine, Simtrol 10 Starfighter Oxadiazon 13 Triclopyr Element 3, Garlon 3, Stinger Clopyralid 9 Tahoe 3 9 Sureguard Flumioxazin 13 Surflan Oryzalin 13 Tahoe 3 Triclopyr 9 Tower Dimethenamid-p 14 Segment Sethoxydim 8 Westar Hexazinone + sulfometuron 14 What Is "lbs. AIA" ? Many of the rates of application in this publication are presented in pounds of active ingredient per treated acre (lbs. AIA). By treated acre, we mean only the area to which the herbicides are directly applied. For example, if there is six feet between rows of trees, and a band three feet wide is sprayed over each row, only one-half of each acre of trees is actually being sprayed. To treat six acres of trees, you would only need to mix enough spray solution to cover three acres of ground. The amount of active ingredient in dry formulations of herbicides is presented as a percent active ingredient. The amount of active ingredient in liquid formulations is presented as pounds of active ingredient per gallon. Dry formulations Examples granular -G Ronstar 2G - 2% active ingredient wettable powders -W or WP Devrinol 50WP – 50% active ingredient dry flowable or -DF or WDG Aatrex Caliber 90 (a WDG) - 90% active ingredient water dispersible granules Liquid formulations emulsifiable concentrate -E or EC Goal 2 XL - 2 lbs. active ingredient per gallon liquid -L Princep 4L - 4 lbs. active ingredient per gallon amine -A Garlon 3A - 3 lbs. active ingredient per gallon water soluble Roundup Pro- 4 lbs. active ingredient per gallon Sample Calculations How much Princep Caliber 90 and Roundup Pro are needed to treat a field measuring 800 ft. by 160 ft. at the rates of 2 lbs. AIA (active ingredient per acre) Princep and 1 lb. AIA Roundup Pro? 800 ft. x 160 ft. = 128,000 sq. ft. ÷ 43560 sq. ft./acre = 2.9 Acres 2 lbs. ÷ 0.9 = 2.2 lbs. (2.2 lbs. Princep Caliber 90 contains 2 lbs. active ingredient). 2.2 lbs. x 2.9 A = 6.4 lbs. Princep Caliber 90 is needed to treat 2.9 A at the rate of 2 lbs. AIA. 1 gal. of Roundup Pro contains 4 lbs. active ingredient. There are 4 qts. in a gal., so each qt. contains 1 lb. active ingredient. 1 qt./A x 2.9 A = 2.9 qts. of Roundup Pro needed to treat 2.9 acres at the rate of 1 lb AIA. ATTENTION PRIOR TO USING ANY HERBICIDE, READ THE INSTRUCTIONS FOR USE AS STATED ON THE LABEL. Why Control Weeds There are many reasons to control weeds in Christmas tree plantings. Weeds: compete for nutrients, water, and light adversely affect needle color cause lower limb loss through light competition lodge in the lower limbs of trees, soiling the trees reduce air drainage and movement increasing tree susceptibility to frost damage and foliar disease provide cover and food for rodents resulting in girdling in winter when food is scarce are a fire hazard when dry and fire sources are in the area interfere with standard Christmas tree maintenance practices (e.g., shearing, insecticide and fungicide applications, mowing) interferes with choose and cut tree sales and customer experience and satisfaction Levels of Control Some growers ignore weeds, while others mow, apply herbicides, plant cover crops, or use a combination of these methods. Some growers that ignore weeds plant their trees on rocky, infertile soil that is not suitable for growing much else other than Christmas trees - not even weeds grow well on these sites. Surprisingly, several Christmas tree species grow in rocky, infertile soils in their native range. This means they will survive and grow on these sites, but they will not produce optimum growth. Growers that rely on low fertility soils to provide their weed control are not producing uniform, high quality trees in a reasonable length of time. Other growers rely entirely on mowing for weed control. For best control with mowing, the planting should be mowed both with and across the rows. This means the plantation must be very carefully planted so that all rows are straight in both directions. Though relying only on mowing eliminates the risk of herbicide injury, there is the constant risk of hitting trees with the mower. Mowing is time consuming and therefore expensive. Also, mowing alone does not provide all the benefits of a weed control program that includes herbicides. Many weeds, especially grasses, stunt the growth of trees even when close-mowed. Combining the careful use of herbicides and mowing provides several advantages over mowing alone. The herbicides can be used in the rows to provide a weed free band 30-36" wide. Weeds growing between the rows can then be mowed quickly with little risk of hitting the trees with the mower. Maintaining the weed free area around the trees limits the competition between weeds and trees and keeps the weeds from interfering with maintenance of the trees. There are several problems associated with letting naturally occurring vegetation grow between the rows. One is varying growth rates of weeds. One part of a field may have quackgrass, which starts growing early in the spring, while another part may be dominated by foxtails, which start growing in early summer. To maintain uniform control in the field it must be frequently mowed. Another problem is the lateral spread into the clean rows by the rhizomes (underground stems) of perennial weeds and the foliage of large or creeping weeds. 4 The optimum level of control would include maintaining a weed free band in the rows and a controlled cover crop between the rows. A properly selected cover crop would crowd out fast growing, aggressive weeds and require little mowing. The Herbicides The development of safe and effective herbicides for use in Christmas tree plantings has revolutionized Christmas tree production. Growers, in the past, avoided high fertility sites and the application of