Pesticide Drift Management Dr. Eric P. Prostko Extension Weed Specialist University of Georgia

Pesticide Drift Management Topics For Discussion  definition  types of drift  factors affecting drift  equipment  management

What is pesticide drift??  the movement of the pesticide away from the target area.  physical drift  vapor drift

Spray drift is undesirable!!  inefficient use of equipment and time  under-application/ineffective control  litigation concerns  unintentional contamination of foodstuffs  air/water pollution  livestock and human health/safety

Corn and Grain Sorghum Yield Loss From Simulated Staple Drift, College Station, Applied 30 DAP

Physical Drift  movement of pesticide away from target during application  droplet size  boom height  weather

Studies have shown that equipment and its operation are responsible for 68-90% of the physical drift problems while weather accounts for 10-32%. D. B. Smith et al., 1982

Physical Drift Droplet Size  measured in microns  hair - 50 microns  micron range  200 micron average  smaller drops increase drift potential (< 100)

Fall Rate of Various Size Droplets

Relationship of Particle Size to Drift Based upon 10’ fall in 3 MPH winds

Physical Drift Droplet Size  nozzle selection  Drift Guard Nozzles * reduces volume of droplets below 200 microns up to 65%  Raindrop Nozzles * 0.7% microns or less

Physical Drift Spray Boom Height Spacing * Wide-angle nozzles can be placed lower to the ground but also produce smaller droplets. * Easy and inexpensive

Physical Drift Weather  wind speed/direction * most important  temperature  humidity  inversions

Physical Drift Temperature Inversions NormalInversion

Physical Drift Other Factors to Consider  nozzle orientation  spray pressure  spray volume

Physical Drift Nozzle Orientation  ground speeds > 10 MPH  45 0 or more from perpendicular 30% < 100 microns 88% < 100 microns

Influence of Spray Pressure on Droplet Size Flat Fan Nozzle GPM

Physical Drift Spray Volume  most effective means to increase spray volume is to increase nozzle orifice size  i.e vs vs. 8004

Vapor Drift  the volatilization or evaporation of a pesticide from the soil or crop surface that occurs after application.  Factors that influence vapor drift include: * vapor pressure/volatility * vapor pressure/volatility * temperature * temperature * wind speed * wind speed

Non-Target Sensitive Crop Vapor drift can occur even days after the application Wind Drift Vapor

Vapor Pressure Values of Various 77 0 F Note: The higher the number the more volatile the chemical.

Pesticide Drift Management Equipment Modifications  shielded spray boom  covered boom  hooded-sprayers  air-assist systems  electrostatic spraying

Pesticide Drift Management Drift 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 Ohio State Univ. Extension, Facts #1203.

Top 10 Tips For Reducing Pesticide Drift  nozzle selection  reduce pressure  lower boom height  increase nozzle size  avoid spraying when winds exceed 10 MPH  lookout for inversions  use additives  calibrate sprayer  keep records  use common sense

References used in the development of this slide set include the following:  Reducing Spray Drift. Ohio State Univ. Extension Bulletin 816, H. Erdal Ozkan.  Herbicide Application Management. Sandoz Crop Protection, 1993.