ALBANY, N.Y. - Spray drift is the movement of a pesticide through the air to a site other than the target area, either during or after an application. Drift can result from agricultural and residential use of pesticides by both ground and aerial applications.
Spray drift may affect sensitive crops, bodies of water, neighboring property or nearby people, domestic animals and wildlife. In addition, pesticides that do not reach their targets are wasted and the applicator may need to use more pesticide, time and money to control pests.
Avoiding spray drift is the legal responsibility of the person applying the pesticide. For specific instructions and precautions, refer to the product label. Some recommendations are listed below.
WEATHER CONDITIONS.
- Avoid application if wind speeds are greater than 10 mph or if winds are gusty.
- Avoid applications during temperature inversions - when air near the ground is cooler than air above it. An inversion can be detected by observing smoke from a ground source - smoke will move horizontally and concentrate in a could instead of spreading upward.
- Avoid applications during high temperatures and low humidity. These conditions increase the pesticide’s evaporation rate, resulting in smaller droplets that are more likely to drift.
EQUIPMENT AND TECHNIQUES.
- Calibrate, maintain and repair spray equipment regularly.
- Use nozzles that produce larger droplets while still providing proper coverage and control.
- Use low pressure sprays (consult nozzle manufacturer instructions) and increase the spray volume and flow rate.
- Use the minimum number of nozzles needed for uniform coverage.
- Drift control additives, which increase average droplet sizes, may be effective in reducing drift from ground applications.
- Point nozzles downward and slightly backward during ground applications.
- Apply as close to the target surface as practical (less than 10 feet for aerial applications).
- Shut off sprayer when making turns.
- Equipment modifications (e.g., boom covers or electrostatic spraying) may help increase application efficiency and reduce spray drift.
- Adjust nozzles for optimum droplet size during aerial applications, based on application type and speed of the aircraft. Generally, pointing nozzles rearward and parallel to the air stream results in larger droplets than pointing nozzles downward or forward. Use a spray boom length less than or equal to three-fourths the length of the wingspan or rotor.
GENERAL INFORMATION.
- If you notice drift occurring during an application, immediately stop spraying until weather conditions improve or equipment/application methods are modified.
- Buffer zones between treated and sensitive areas may help reduce damage resulting from drift to these locations.
- Giving neighbors prior notice of application may reduce problems should drift occur.
The above information is reprinted from the New York State Department of Environmental Conservation’s pamphlet titled "Pesticide Spray Drift."