On Crops: Potatoes, eggplant, peppers, tomatoes (rarely)
Native to South America and Mexico, Colorado potato beetles are now found in most temperate climates where potatoes are grown
Adult Colorado potato beetles have striped yellow and black backs, with orange heads showing black dots. They are about the size of a fingernail. Adult females lay clusters of yellow eggs on the undersides of leaves, from which hatch reddish, soft-bodied larvae. The larvae quickly gain size as they feed, and are sometimes called sow bugs or potato bugs.
Colorado potato beetle larvae feed heavily on new foliage and flowers, and can strip plants of all leaves when left uncontrolled.
Adult potato beetles walk to find host plants, and a straw mulch slows them down, as does a deep trench around the potato patch lined with slick plastic. In gardens where this pest is seen every year, grow potatoes under protective row covers. Hand picking gives good control of small outbreaks.
Scout early and often for Colorado potato beetles, which are best managed when they first appear. Grab and crush any adults seen in spring. Hand pick larvae and adults and drop them into a container of soapy water. Should you encounter egg clusters, pinch off the leaf and compost it. In situations where this pest is out of control, the biological pesticide called spinosad gives good control.
Sow a few buckwheat seeds among your potatoes to attract beneficial insects. Do not try synthetic chemicals against Colorado potato beetles, because they have developed a high level of resistance.