How can I control Colorado potato beetles?
The Colorado potato beetle is difficult to control. Hand picking is a control option for individuals with small gardens. Hand-pick beetles, eggs, and small larvae from infested plants as soon as possible (practical for a few insects on a few plants, but impractical for larger gardens). It’s especially important to remove overwintering beetles that appear on young plants in spring.
In large gardens, insecticides are often the best option. When insecticides are necessary, consider timing, coverage, and insecticide choice. Timing is critical. Small larvae are much easier to control and spraying when the larvae are small is much more effective than spraying when the larvae are large. Early treatment is also necessary to prevent crop loss. Complete and thorough coverage of infested plants is necessary for good control. Control is generally more effective with liquid sprays than with dust applications.
Because of decades of repeated insecticide use, the Colorado potato beetle is resistant to many widely used garden insecticides, such as Sevin. The first-choice products are the synthetic pyrethroids, such as permethrin, cyfluthrin, and esfenvalerate. Look for products labeled for use on potatoes in the home garden and apply according to label directions. Spray early and spray often. Biorational pesticides, such as spinosad, Bt tenebrionis, and Neem (azadirachtin), are only effective on very young larvae.