Rotating insecticides is key for organic growers. According to Ayanava Majumdar, Extension entomologist with Auburn University, if growers do not rotate their insecticides, they run the risk of harming natural enemies.
Majumdar has been testing organic insecticide rotations in Alabama over the past six years. He noticed that using one insecticide did not work very well against high populations of insects. “By rotating insecticides, you are reducing the use of expensive insecticides and you can also target multiple species,” Majumdar explains.
According to Majumdar, growers can also incorporate selective insecticides into rotations. For example, Bacillus thuringiensis (Bt) products specialize in killing caterpillars. So, if growers notice high populations of caterpillars in the field, they can incorporate Bt products in their rotation of broad-spectrum insecticides to attack those caterpillars.
Majumdar recommends that growers make a habit of scouting for pests weekly or often. By recognizing the species and volume of pests in the field, choosing an insecticide can be a simpler process.
He also reminds growers that in small or organic production systems, the use of insecticides should be minimal. “We have problems with insecticide resistance, and insecticides, if used too much, can hurt natural enemies. We need natural enemies on organic farms,” he says.
Growers have some other pest management methods they can use besides insecticides. Majumdar recommends looking into the following practices: pest exclusion systems, trap cropping, beneficial insects and practicing good sanitation tactics.
Hear Majumdar’s full interview:
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