Pesticide applicators should consider the following whenever using pesticides:
- Learn where sensitive crops are located in relationship to your application site. Always be aware of what is downwind of your application site.
- Measure and record weather conditions.
- Measure wind speed and direction before, during, and after the application. Always follow label information, but generally, wind speeds between 3 and 10 mph are preferable. On a calm day with no wind, a temperature inversion (trapped layer of air) could result in the horizontal movement of pesticides. This is more common in early mornings and evenings.
- Keep track of temperature and relative humidity. High temperatures and low relative humidity leads to more evaporation of pesticides. These vapors can travel long distances.
- Modify your application techniques, following requirements and recommendations on the pesticide label.
- Reduce spray pressure to produce larger spray droplets, as these are less likely to drift.
- Use low-drift nozzles, such as those with air-induction technology. Replace all worn nozzles.
- Keep the spray boom as low as possible while allowing good coverage and penetration. Boom shields and windscreens may help reduce drift by directing the application and reducing wind effect.
- Include a drift control agent in the spray tank.
- Read more about managing drift.
- Thoroughly clean application equipment after use to avoid contaminating future tank loads with leftover pesticide residue.
Herbicide Stewardship and Drift Prevention
- Avoid applying near crops in sensitive growth stages (flowering, leaf emergence).
- Check the DriftWatch site for sensitive crops near the application area.
- Map surrounding sensitive crops and communicate with neighbors. Check weather forecasts for wind direction and speed, temperature, and rain.
- Avoid applying pesticides with volatile active ingredients during hot afternoons.
- Watch for temperature inversions and avoid applying during them.
Application Method and Technique
- Boom height is critical: a lower boom reduces drift.
- Application speed: slower is better.
- Keep equipment calibrated and clean.
- Nozzle choice: use low drift types.
- Air induction nozzles: 4-10x fine particle reduction.
- Use spray pressure recommended for nozzle and by label.
- Check the pesticide label for susceptible crops to avoid.
- Trees, gardens, and ornamentals may be susceptible.
Read about herbicide damage to trees from the Nebraska Forest Service.
- Use Crop Calendar and Sensitive Crop Maps.
- Check wind direction leaving the target area.
- Low humidity will evaporate small droplets.
- Temperature affects droplet size and product volatility.
- Inversions have potential to keep fine particles together.
- Use your weather station information to plan applications.
(Provided as a service by the Industry Task Force II on 2, 4-D Research Data.)
Protecting Pesticide Sensitive Crops
- EPA Reducing Drift Information
- EPA DRT Voluntary Program
- Soybean Best Management Practices from the Honey Bee Health Coalition
- Dicamba Information - UNL
- Dicamba Information - NDA
Reducing Risk of Herbicide Drift Injury
Sensitive Sites: Grapes and Vineyards
Sensitive Sites: Bees and Pollinators