Colorado potato beetle

Gardeners growing potato, eggplant, pepper, or tomato may be observing Colorado potato beetle on their plants. Adults are oval in shape and 3/8 inch long and have 10 narrow black stripes on their wing covers. Yellowish orange oval eggs, laid in clusters, may be found on the underside of leaves. Young larvae are brick red with black heads while older larvae are pink to salmon colored with black heads. All larvae have two rows of dark spots on each side of their bodies. Both larvae and adults feed on plant foliage. If left untreated, they can completely defoliate plants leading to reduced yields. Colorado potato beetle has one to two generations a year and are seen from spring until harvest.

If Colorado potato beetle are present in your garden, one control option is handpicking. Pick off adults and larvae and place them into a pail filled with soapy water. Flip over leaves and crush the yellowish orange eggs. Handpicking and egg removal takes time, patience, and needs to be repeated throughout the growing season making it more conducive for small gardens.

Another control option is to use an insecticide. Spinosad is a low impact insecticide that is effective against Colorado potato beetle. Traditional insecticides containing the active ingredients carbaryl, cypermethrin, deltamethrin, lambda cyhalothrin, imidacloprid, permethrin, and pyrethrins are generally not effective as most populations of Colorado potato beetle have developed resistance to them. Anytime you use an insecticide and it does not seem to kill the Colorado potato beetle, switch to a different active ingredient. Source: Jeffrey Hahn, Extension Entomologist (retired). More information on Colorado potato beetle can be found at: http://z.umn.edu/potatobeetle

If you have questions about Colorado potato beetle in your garden please call me at the University of Minnesota Extension office, Clay County at 218-299-7338, 1-800-299-5020 or at nels1657@umn.edu. Check out our website at https://local.extension.umn.edu/local/clay

The University of Minnesota, including the University of Minnesota Extension is an equal opportunity educator and employer.