Apri’s Ag Advice

Apri's Ag Advice by April Borders With the cost of pesticides today and all the scrutiny that the agriculture industry has been under, we need to try to get a handle on spray drift.

So what can you do to reduce drift? Here are some suggestions.

1. Choose your chemical carefully. Many chemicals come in different formulations. An ester formulation is more susceptible to vapor drift when temperatures are high, while an amine formulation of the same product will be much less likely to volatilize.

2. Check the pressure that you are using to apply your chemical. As the pressure increases, droplet size decreases. Therefore, lower pressure reduces drift. Under most conditions, do not exceed 40 to 45 psi unless you are using a venturi-style tip designed for high pressure.

3. Avoid high ground speeds or major speed changes. Spraying at high speeds is no different than spraying in high winds. High speeds also create a vacuum behind the sprayer, which can cause distribution in this area to be worse than along other areas of the boom.

4. Boom setup is very important. It consists of three issues: height, levelness and stability. Nozzle manufacturers provide optimum height recommendations for nozzle type and spacing. Follow these as closely as possible. If the boom is too high you will get drift, if it is too low you risk an uneven distribution of pesticide across the boom width. Make sure that your boom is level for uniform chemical distribution. Also make sure that your boom is stable. A boom that bounces excessively provides for poor chemical distribution.

5. Select a nozzle style that produces coarser droplets. Increase nozzle size, a larger capacity nozzle will reduce drift.

6. Spray when wind speeds are less than 10 mph. If there is a slight wind, spray when the wind is moving away from the sensitive crop. Leave a buffer zone by the sensitive crop and spray that area when conditions are more conducive.

7. Keep a close eye on environmental conditions � wind speed, wind direction and temperature. Be aware of temperature inversions. When the air is very still and temperatures near the soil surface are cooler than the air above, no mixing occurs. Calm air can reduce air mixing so the spray moves slowly downward. The pesticides can hover in a dense cloud above the soil surface and be carried off site by a gentle breeze.

8. Consider using new technology like drift reduction nozzles or boom shields.

9. Consider using a drift control additive. Drift control additives increase the average droplet size produced by the nozzle. They can affect your spray pattern so you might need to recalculate nozzle height.

For more information contact your local Extension Office at 677-7111.

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