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Colorado potato beetle

Quick facts

  • The Colorado potato beetle (Leptinotarsa decemlineata) is a major potato pest throughout North America. It can also feed on eggplant, tomatillo and related crops.
  • Adults become active in spring, about the same time potato plants emerge from the ground.
  • Larvae and adults feed on leaves and can completely defoliate plants.
  • Many pesticides are ineffective because of the pesticide resistance of the Colorado potato beetle.
  • A combination of pest management tactics can reduce Colorado potato beetle numbers.

How to identify Colorado potato beetles

Colorado potato beetle adults. Photo: David Cappaert, Bugwood.org

Adults

  • Beetles are oval and 3/8 inch long.
  • Have a yellow-orange prothorax (the area behind the head) and yellowish-white wing covers with 10 narrow black stripes.
  • Females lay clusters of bright yellowish-orange oval eggs on the underside of leaves.

Larvae

  • When young larvae first hatch, they are brick red with black heads.
  • Older larvae are pink to salmon colored with black heads.
  • All larvae have two rows of dark spots on each side of their bodies.

Biology of Colorado potato beetle

Colorado potato beetle egg mass. Photo: David Cappaert, Bugwood.org
Colorado potato beetle larva. Photo: Tavo Romann, Wikimedia.org
  • Colorado potato beetle adults spend the winter 5-10 inches underground in potato fields, field margins, windbreaks and gardens.
  • Adults feed for a short time in the spring and then begin to mate and lay clusters of 10-30 eggs on the undersides of leaves.
  • Each female can lay up to 350 eggs during her adult life which can last several weeks.
  • Eggs begin to hatch within 2 weeks, depending upon temperatures.
  • Larvae cluster near the egg mass when young but begin to move throughout the plant as they eat the leaves.
  • Larvae can complete development within 10 days if average temperatures are in the mid-80s F while it can take over a month if temperatures average near 60 F.
  • The fourth instar larvae drop from the plant, burrow into the soil and transform into pupae.
  • In southern and central Minnesota there is generally a second generation. By midsummer, all stages of Colorado potato beetles, eggs, larvae and adults can be present in one area.

Damage

Colorado potato beetle larvae defoliating a potato plant. Photo: Whitney Cranshaw, Colorado State University, Bugwood.org
  • Old larvae (the last or 4th larval instar) are responsible for as much as 75% of feeding damage.
  • Potatoes can usually tolerate up to 30% defoliation before flowering.
  • They are much more sensitive when tubers are beginning to size up and can only tolerate about 10% defoliation.
  • Tuber bulking begins soon after flowering, making this time critical for beetle management.

Managing Colorado potato beetles in home gardens

Treatment of Colorado potato beetles in home gardens can be challenging. Use a combination of different pest management tactics to reduce Colorado potato beetle numbers.

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Managing Colorado potato beetle on farms

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Authors: Marissa Schuh, Extension educator, Jeffrey Hahn and Suzanne Burkness, College of Food, Agricultural & Natural Resource Sciences

Reviewed in 2024

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