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2011: Weed Control and Crop Tolerance with 2,4-D in the Southeast & MidSouth

AUTHOR
Stanley Culpepper, University of Georgia
Larry Steckel, University of Tennessee

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TABLE OF CONTENTS
  1. 2011: Weed Control and Crop Tolerance with 2,4-D in the Southeast & MidSouth
  2. 2,4-D and the NCWSS
  3. 2,4-D and the Southern Weed Conference
  4. 2,4-D -- Early scientific literature
  5. 1948 Congressional Hearings about 2,4-D Drift to Cotton
  6. 1948 Congressional Hearings about 2,4-D Drift to Cotton
  7. 1948 Congressional Hearings about 2,4-D Drift to Cotton
  8. 1948 Congressional Hearings about 2,4-D Drift to Cotton
  9. 2,4-D Products
  10. 2,4-D Labeled Uses
  11. Uses of 2,4-D
  12. Total 2,4-D Usage on an Area-Weighted Basis
  13. Estimates of Usage SE & MidSouth
  14. Small Grains in the SE & MidSouth
  15. 2,4-D Use in Small Grains
  16. Timing Effect on Small Grains
  17. 2,4-D commonly used in orchards in SE and MidSouth
  18. 2,4-D commonly used in Peaches
  19. 2,4-D and Forage Grasses SE and MidSouth
  20. 2,4-D and Forage Grasses SE and MidSouth
  21. 2,4-D and Forage Grasses SE and MidSouth
  22. 2,4-D and Forage Grasses SE and MidSouth
  23. 2,4-D Turf
  24. Phenoxy overdose on St. Augustinegrass
  25. 2,4-D
  26. Escalade at 3 pt/acre (2,4-D +dicamba + fluroxypyr)
  27. 2,4-D in Corn
  28. Controlling GR Horseweed in RR Corn
  29. Corn Injury with 2,4-D
  30. 2,4-D For Burndown
  31. 2,4-D in Fallow and Burndown
  32. Burndown: Primarily for Cotton in SE
  33. Glyphosate + 2,4-D vs Untreated
  34. Primrose Response to 2,4-D Amine (4 lb/gal).
  35. Photo
  36. Will it grow back???
  37. Horseweed Control; March 30th Application
  38. 2,4-D vs Clarity for Horseweed
  39. Edgecombe Co, NC 2008, 8 weeks after burndown
  40. 2,4-D at Planting vs Ignite
  41. Spray Drift and Tank Contamination
  42. Arkansas 2,4-D Application Restriction
  43. FLorida 2,4-D Application Restriction
  44. 2,4-D Uses - Summary
  45. Questions or Comments?



SLIDE CONTENTS
  1. 2011: Weed Control and Crop Tolerance with 2,4-D in the Southeast & MidSouth Dallas Peterson KSU Murphy, Mccullough, Prostko, Sosnoskie UGA York, Mitchem NCSU First patent on 2,4-D in 1944 Culpepper (UGA) and Steckel (UT)
  2. 2,4-D and the NCWSS 1944 – First meeting of NCWCC Kephart – Chemical Weed Killers After the War “some of the so-called hormone chemicals are amazingly injurious to plants in almost unbelievably small concentration” 1948 – Over 90% of the 334 abstracts in the NCWCC Research Report addressed weed control and crop tolerance to 2,4-D (Small grains, corn, sorghum, flax, soybeans, sugarbeets, asparagus, lima beans, onions, potatoes, table beets, strawberries, raspberries, clover, trees, brush, pasture)
  3. 2,4-D and the Southern Weed Conference *Doesn’t include talks that describe ‘effects of herbicides on growth and cytological processes’ or ‘crop response to vapor drift’ or ‘pre-emergence weed control in corn’ or other topics which could refer to experiments with 2,4-D.
  4. 2,4-D – Early scientific literature Web of Science® search 1945-1955 196 articles in which 2,4-D was the topic, including: 2,4-D INJURY TO COTTON FROM AIRPLANE DUSTING OF RICE (1948) PHYTOPATHOLOGY   38: 638-644   THE VOLATILITY OF SEVERAL SALTS AND ESTERS OF 2,4-D AS DETERMINED BY THE RESPONSE OF TOMATO, BEAN, AND COTTON PLANTS (1949) PROCEEDINGS OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE   53: 281-290   2,4-D HERBICIDES POSE THREAT TO COTTON AND OTHER SUSCEPTIBLE CROPS (1953) SCIENCE   118: 782-783  
  5. 1948 Congressional Hearings about 2,4-D Drift to Cotton
  6. 1948 Congressional Hearings about 2,4-D Drift to Cotton
  7. 1948 Congressional Hearings about 2,4-D Drift to Cotton
  8. 1948 Congressional Hearings about 2,4-D Drift to Cotton
  9. 2,4-D Products Hundreds of Products on the Market Multiple formulations: Esters Amines and Salts Acid Liquid and Dry products Labels vary by formulation and product
  10. 2,4-D Labeled Uses Crops Corn Small grains Sorghum Rice Sugarcane Grass for Seed Fruit and Nut Trees Vegetables Rangeland, Fallow, and Noncrop Uses Pasture and Rangeland Fallow, No-Till Burndown Turf Forestry Christmas Trees Rights of Way Aquatic Ditchbanks
  11. Industry Task Force II on 2,4-D
  13. Crops Corn: 5-15% Small grains: 35% Sorghum: 5-10% Orchards: 40-50% Vegetables: <1% Non Crop Pasture & Rangeland 20% Burndown 10-20% Turf 25% Rights of Way 20% Estimates of Usage SE & MidS
  14. Small Grains in the SE & MidS Radish/Mustard Control 2,4-D best option
  15. 2,4-D Use in Small Grains Formulations: mostly esters Rates: 0.5 to 0.75 lb ae/acre Timing: Postemergence fully tillered Species: Wild radish
  16. Timing Effect on Small Grains
  17. 2,4-D commonly used in orchards in SE and MidS Apple: do not spray w/n 14 d bloom; avoid contact of tree. Pecan: do not spray in 60 d of harvest; avoid contact of tree. Peach: applications before bud break; no contact of tree. Amine formulation only. Often up to 1 lb ae when alone in grass strip. Often mixed with glyphosate at 0.5 lb to improve control of morningglory, primrose, radish next in herbicide strip. Will become more important with GR horseweed.
  18. Peaches = winter annual broadleaf weeds growing between strips as part of an integrated approach to control cat-facing insects. Also leaves grass groundcover to prevent erosion and facilitate equipment movement. 2,4-D commonly used in Peaches
  19. 2,4-D and Forage Grasses SE and MidS The beginning of selective weed control in grass pastures and hay fields. Effective for control of: Thistles (bull and musk) - Buttercup sp. Common Ragweed - Bitter sneezeweed Cutleaf eveningprimrose - Wooly croton Dandelion - Plantain sp. Horseweed - Spiny amaranth
  20. Positive attributes Grasses are highly tolerant Seedling grasses @ 4-5 lf stage Low in cost, usually the first choice of farmers Short soil persistence (avg. half-life = 10 d) does not interfere with rotations with other crops In southern U.S. grasses and legumes may be reseeded 1 to 2 months after application 2,4-D and Forage Grasses SE and MidS
  21. Positive attributes (cont.) MOA of 2,4-D is needed as part of herbicide-resistant weed prevention strategies Sulfonylurea herbicide use is increasing in forage grasses, particularly bermudagrass A common tank-mixture partner with other herbicides (i.e. lower cost, increase control spectrum. Dicamba, clopyralid, triclopyr, picloram, aminopyralid, metsulfuron (Cimarron Max) 2,4-D and Forage Grasses SE and MidS
  22. Grazing and Haying Restrictions compatible with animal production systems Grazing Restrictions – may vary by label 7 d lactating dairy cattle 0 d beef cattle, horses, others Hay Restrictions 7 to 30 d all livestock species Slaughter – remove animal from 2,4-D treated pasture 3 d before slaughter 2,4-D and Forage Grasses SE and MidS
  23. 2,4-D Turf Phenoxy Herbicide Disrupts cell division, cell enlargement, protein synthesis and hormonal balance. Beneficial chemistry in rotation with sulfonylureas and triazines to manage weed resistance in turfgrass. Turfgrass Use Most major warm and cool-season turf species. St. Augustinegrass, centipedegrass, and bentgrass golf greens may be sensitive to applications. Weeds Controlled Excellent postemergence activity on annual and perennial broadleaf weeds.
  24. Phenoxy overdose on St. Augustinegrass Photo: T. Murphy
  25. 2,4-D Common Uses Lawns, golf courses, sports fields, and sod farms 2,4-D; 2,4-DB, and 2,4-DP used in turfgrass Herbicide Combinations 2,4-D is most commonly used in prepackaged formulated mixture products for turf weed control. Examples of tank-mix partners: dicamba, MCPP, fluroxypyr, clopyralid, triclopyr, sulfentrazone, quinclorac.
  26. Escalade at 3 pt/acre (2,4-D +dicamba + fluroxypyr) 4 WAT 2009, UGA Photo: P. McCullough
  27. 2,4-D in Corn
  28. Controlling GR Horseweed in RR Corn Height Guidelines for 2,4-D: Burndown 1 to 2 pts/A 7 to 14 DBP Do not apply on coarse soils Applied PRE (Plant deep as practical)??? 8 oz/A, Do not apply on coarse soils Post (Spike to 8”) 8 oz/A (if corn is growing rapidly)??? Should only be sprayed if hybrid is tolerant???
  29. Corn Injury with 2,4-D
  30. 2,4-D For Burndown
  31. 2,4-D in Fallow and Burndown Formulations: amine or ester Rates: 0.125 to 1 lb ae/acre Timing: Crop and formulation dependent Weeds: annual and perennial broadleaf weeds Historical perspective: Limited use in early years because of tillage systems Common tank-mix partner with glyphosate in 1970’s, 80’s, and 90’s to minimize cost of treatment Now it’s a common tank-mix to improve control of problematic weeds
  32. Burndown: Primarily for Cotton in SE Primrose was driver of 2,4-D use because of its tolerance to glyphosate and it is present in every field. Radish to a small degree.
  33. Glyphosate + 2,4-D Untreated
  34. Primrose Response to 2,4-D Amine (4 lb/gal). Tifton, GA 2003. % control 42 days after treatment Primrose 6-9”, prebloom 1 pt/A 0.75 pt/A 0.5 pt/A 0.25 pt/A
  35. Photo credit: Larry Steckel
  36. Will it grow back???
  37. Horseweed Control 0 20 40 60 80 100 Ignite 32 oz Ignite 32 oz + 2,4-D 32 oz Roundup WM 22 oz + Clarity 8oz Ignite 32 oz + Clarity 4 oz Ignite 32 oz + Clarity 8oz LSD = 13 % Control 40 DAT March 30th Application Roundup WM 22 oz Gramoxone Max 32 oz + Clarity 8 oz Gramoxone Max 32 oz
  38. 2,4-D vs Clairty for Horseweed There appears to be no difference in horseweed control between the two 2,4-D salts In our data 2,4-D showed similar horseweed control to Clarity In the field 2,4-D has not been as consistent
  40. 2,4-D at Planting Ignite
  41. Spray Drift and Tank Contamination Spray drift and tank contamination has been an ongoing issue with the use of 2,4-D since its introduction. Improved formulations and application techniques have lessened the problem over time, but still room for improvement.
  42. Arkansas 2,4-D Application Restriction Applies to North West AR Counties 2,4-D can be applied up to April 15 No 2,4-D can be sprayed for any reason after this date Exemptions can be applied for: Quite a bit of paper work Representative from AR plant board as well as land owner must be present at time of application Rarely occurs
  43. FLorida 2,4-D Application Restriction (FL’s Organo-Auxin Herbicide Rule No. 5E-2.033) No high volatile forms Except for use as PGR on citrus No high volatile forms Except for use as PGR on citrus Other forms Can be used if follow specific guidelines Ex. 4 mph crosswind = 1/8 mile Ex. 4 mph upwind = 5 feet Ex. 4 mph downwind = ¼ mile
  44. 2,4-D Uses - Summary 2,4-D has been and continues to be a widely used herbicide. 2,4-D is a very versatile herbicide used in a wide variety of crops and situations. 2,4-D is a valuable tank-mix partner with other herbicides for broad-spectrum, cost-effective weed control. 2,4-D is a useful herbicide to help manage herbicide resistant weeds.
  45. Questions or Comments?