Herbicide Application Update Herbicide Application Update New Nozzle Design for Reduced Drift but….What About Control? Robert E. Wolf Biological and Agricultural Engineering Dept. Kansas State University

Changes in the Application Industry! Inefficient Increased cost of pesticides Changing rates-less product More pest specific products More sophisticated equipment - $$$ Variable rates with application maps - GPS Environmental impact (water and air)

Why Interest in Drift? Spotty pest control Wasted chemicals Off-target damage Result - higher costs - $$$ More wind?? (Timing) Environmental impact (Water and Air Quality) Public more aware of pesticide concerns! (Negative) Spraying in more populated areas? (Suburbs)

Acreage of Roundup ready (genetically modified) soybeans under cultivation in the United States Million Million Million Million R-U Ready Soybean Explosion

Drift: Movement of spray particles and vapors off-target causing less effective control and possible injury to susceptible vegetation and wildlife. Types of Drift: – Vapor Drift - associated with volatilization – Particle Drift - movement of spray particles either during or after the application!!!

Factors Affecting Drift: Spray Characteristics ächemical äformulation ädrop size äevaporation Equipment & Application ä nozzle type ä nozzle size ä nozzle pressure ä height of release Weather ä air movement (direction and velocity) ä temperature and humidity ä air stability/inversions

One micron (  m ) =1/25,000 inch Particle drift results by creating smaller drops. Spray droplets are measured in microns and expressed as: Volume Median Diameter (VMD) Relationship of Drift to Drop Size

Comparison of Micron Sizes for Various Items: (approximate values) pencil lead 2000 (  m ) paper clip 850 (  m ) staple 420 (  m ) toothbrush bristle 300 (  m ) sewing thread150 (  m ) human hair100 (  m ) 150

1/2 of spray volume = larger droplets VMD 1/2 of spray volume = smaller droplets

Cutting Droplet Size in Half Results in Eight Times the Number of Droplets 500 Microns 250 Microns 250 Microns 250 Microns 250 Microns 250 Microns 250 Microns 250 Microns 250 Microns

Why is the Nozzle Important? Amount of spray applied Uniformity of the spray Coverage on the target Amount of off-target drift

What’s new in nozzle technology? Nozzles designed to reduce drift Improved drop size control

Air-Induction/Venturi Nozzles Where air is drawn into the nozzle cavity and exits with the fluid.

TurboDrop Venturi Nozzle Draw air into the nozzle via venturi (Pressure drop) Color coded Venturi Exit pattern tip used to create a spray pattern Designed for 40 psi and higher New low-pressure XL design (15-120)

Strategies to Reduce Drift Select nozzle to increase drop size. Increase flow rates - higher application volumes. Use lower pressures. Use lower spray (boom) heights. Avoid adverse weather conditions. Consider using buffer zones. Consider using new technologies: –drift reduction nozzles –drift reduction additives