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Understanding Herbicide Additives
Dr. Eric P. Prostko
Extension Weed Specialist
University of Georgia
Slide Presentation (PowerPoint, 596 KB)
TABLE OF CONTENTS
Understanding Herbicide Additives
Herbicide Additives: When do you need them??
Herbicide Additives: A balancing act
Herbicide Additives: What do they do??
Herbicide Additives: Types
Herbicide Additives: Non-Ionic Surfactants (NIS)
Herbicide Additives: How surfactants work
Herbicide Additives: Organosilicone Surfactants
Herbicide Additives: Crop Oil Concentrates (COC)
Herbicide Additives: Fertilizers
Herbicide Additives: Buffers
Is the pH of spray water really important?
Rate of Herbicide Degradation in Water at pH of 5, 7, and 9
Herbicide Additives: Compatibility Agents
Herbicide Additives: Drift Control Agents
Drift Fallout As Influenced By Pressure and Nalcotrol
Herbicide Additives: Stickers
Herbicide Additives: How much do they cost??
Herbicide Additives: Do they work???
The influence of additives on Classic (0.5 oz/A) performance in soybeans - 21 DAT
Commercial surfactant effects on the performance of Roundup/Honcho
Influence of additives on sicklepod control with Cadre - 68 DAT
Herbicide Additives: Final Thoughts
Understanding HerbicideAdditives Dr. Eric P. Prostko Extension Weed Specialist University of Georgia Tifton
Herbicide AdditivesWhen do you need them?? postemergence applications certain weeds stressful conditions cheap insurance? may increase crop injury
PPT Slide Crop Injury Enhanced Performance Herbicide Additives A Balancing Act
Herbicide AdditivesWhat do they do?? modify or maximize performance increase absorption and retention * decrease surface tension of water * prevent interaction with Ca, Na * increase permeability of cell membrane and cuticle
Herbicide AdditivesTypes non-ionic surfactants (NIS) organosilicone surfactants crop oil concentrates (COC) fertilizers (N) buffers compatibility agents drift reduction agents stickers
Herbicide AdditivesNon-Ionic Surfactants (NIS) aliphatic alcohols + siloxane + fatty acids decrease surface tension of water need at least 80% active ingredient 0.25% v/v Activator 90, X-77, Latron AG-98, Induce
PPT Slide How Surfactants Work
Herbicide AdditivesOrganosilicone Surfactants silicone based 0.025 - 0.25% v/v Silwet L-77, Kinetic
Herbicide AdditivesCrop Oil Concentrates (COC) petroleum or vegetable oil based 83-85% oil + 15-17% NIS 1% v/v help move herbicide across cuticle reduce surface tension of water reduce drying time Agri-Dex, Peptoil (petroleum) Sun-It, Prime Oil II (vegetable)
Herbicide AdditivesFertilizers 32% UAN (1 qt/A) ammonium sulfate (17 lbs/100 gallons) used with COC or NIS increase leaf burn increase membrane permeability prevent interaction with Ca, Mg, and Na
Herbicide AdditivesBuffers maintain or reduce pH prevent alkaline hydrolysis (> 7 pH) Buffer P.S, Penetrator Plus
Is the pH of spray water really important? may affect some insecticides has not affected the performance of herbicides in most studies length of time in tank is relatively short
Rate of Herbicide Degradation in Water at pH of 5, 7, and 9 C. Boerboom. 1995. University of Wisconsin Water pH
Herbicide AdditivesCompatibility Agents maintain emulsion stability/liquid fertilizer 0.12-0.50% v/v depending upon fertilizer Blendex, Merge, Unite,
Herbicide AdditivesDrift Control Agents “thickeners” increase droplet size of pesticide/water mixes $0.10-$1.00/A 38F, Anchor, Array, Border, Chem-Trol, Corsair, Direct, Drifgon, Driftgard, Drop Zone, Get Down, Lo-Drift, More, Nalcotrol, Submerge, Sta-Put, Windfall
Drift Fallout As Influenced By Pressure and Nalcotrol Source: W. Bowers. 1975. Ohio State Univ. Extension, Facts #1203.
Herbicide AdditivesStickers “adhesives” maintain protective sprays fungicides, insecticides contain latex or casein AAdhere, Bond, Surfix
Herbicide AdditivesHow much do they cost?? Chart based upon 20 GPA sprayer output
Herbicide AdditivesDo they work???
The influence of additives on Classic (0.5 oz/A) performance in soybeans - 21 DAT Source: Fielding and Stoller. 1990. Weed Tech. 4:264-271. S = X-77 @ 0.25% v/v N = 28% UAN @ 1 gal/A
Commercial surfactant effects on the performance of Roundup/Honcho Source: North Dakota State University, 1993-95
Influence of additives on sicklepod control with Cadre - 68 DAT A. S. Culpepper, 1999 LSD 0.05 = 5 Applied to 4-8” CASOB
Herbicide AdditivesFinal Thoughts read label COC > NIS avoid “miracle” products