|Pesticide drift impacts crops, workers and the environrnment.|
|Growers can take some basic steps to minimize drift.|
In an Almond Doctor column, UC Cooperative Extension (Fresno County) adviser Kurt Hembree offered these tips to minimize drift from a ground sprayer:
1. Don’t spray when it’s windy: Do not spray in winds above 6 – 10 mph.
2. Be cautious on calm days: Do not spray under dead calm conditions in early morning, evening or the night. Calm conditions are often associated with temperature inversions which can result in long-distance spray drift (1 mile or more).
3. Check the buffer zones: Refer to the product label to determine adequate buffer zones outside of the field treated. Do not spray if the wind is blowing towards a nearby sensitive crop, garden, waterway, or other sensitive area.
4. Use a shield: Consider equipping your sprayer with a protective shield. A number of designs are available that can reduce drift between 35 and 75 percent. Avoid spraying trunk-to-trunk with unshielded spray booms.
5. Use a spray drift retardant: Spray drift retardants are available that can be added to many products to help reduce off-target drift.
6. Check the formulation: Use amine formulations of 2, 4-D when possible. Use special care when using ester or other volatile herbicides. Avoid spraying these products on or immediately before hot days.
7. Sprayer type: Sprayers designed to apply herbicides at low volumes (<10 gpa), such as controlled droplet applicators, produce extremely fine droplets which can drift long distances. Advances in sprayer technology allow for certain post emergence herbicides (like glyphosate) to be applied through low volume, shielded equipment or in low doses based on weed populations present at the time of treatment.
8. Watch the nozzle pressure: Avoid nozzle pressures above 45 psi for conventional flat fan tips. Excessive pressure can create fine droplets that are prone to drift. Use a minimum of 10 gallon/acre, unless otherwise specified on the label.
9. Nozzle height: Operate nozzles at their lowest recommended height. For 80 degree tips, this is 18 inches, and for 110 degree tips, this is 12 inches. Orienting nozzles forward also allows for further height reductions. 10. Nozzle selection: Special nozzles are available by various manufacturers that create coarse, low-drift sprays. These nozzles can reduce drift by 50 to 95 percent.