Ground machines or aircraft may be used to apply most insecticides. Spray applications are more effective and drift is reduced when wind does not exceed 10 miles per hour. Avoid spraying when the plants are wet.
Because pressure, ground speed, and nozzle size and number influence the rate of spray solution out- put per acre, calibrate the sprayer carefully and often to make sure you are applying the recommended amounts of insecticide. Usually one nozzle per row is adequate for young row crops; for larger plants, two or three nozzles per row may be needed.
Some insecticides and miticides applied with irri- gation water (chemigation) through center pivot and stationary irrigation systems can effectively control some corn pests. Chemigation can reduce application costs and may require less insecticide because it cov- ers the crop more thoroughly than do conventional application methods. Chemigation requires an initial investment in chemical injection equipment and addi- tional management time.
Safety features and practices are necessary for safe and effective chemigation. Of key importance is preventing groundwater contamination. For some insecticides, chemigation is prohibited because they are either highly toxic to mammals or are ineffective when applied in irrigation water.
Refer to the pesticide label to determine whether chemigation is approved. If so, follow the safety equip- ment and procedures that are required by federal law and are listed on the product label.
The label also may provide instructions for mix- ing, diluting, and agitating the product; state the amount of irrigation water to apply during chemiga- tion; and recommend specific adjuvants to increase pesticide efficacy by reducing washoff.
During windy weather, do not use irrigation sys- tems with nozzles positioned above the crop canopy for chemigation because they may cause pesticide drift from the treated field. Also, shut off the endguns during chemigation. Wear personal safety equipment while mixing and loading the insecticide. Avoid con- taminating the site with spilled pesticide, and dispose of the pesticide containers properly.
Carefully maintain and calibrate the pesticide injection pump unit to apply the insecticide uniformly at the desired rate in the irrigation water. Inaccurate calibration can result in under application, which reduces insecticide effectiveness, or over application, which increases costs and may contaminate the crop and the environment.