Colorado Potato Beetle
(Order Coleoptera, Family Chrysomelidae)
Leptinotarsa decemlineata, Adult. (photos by Tim Eberl)
(Kansas: Pawnee County. Private Property [Eakins Farm], 38°11′36″N 99°31′35″W. Tall weeds a few yards from the garden. September 17, 2011.)
Adult Diagnosis: Colorado Potato Beetles are a very recognizable species of the family Chrysomelidae. Adults are a bright yellowish-brown color and have five black stripes running over each of the elytra. Colorado Potato Beetles are oval in shape, convex, and are usually around 3/8 inch in length. The pronotum is often dotted with black spots and the antennae are thread-like and are less than half the length of the body. Like most other members of the Chrysomelidae family, the Colorado Potato Beetle has a tarsal formula that appears to be 4-4-4, but is actually 5-5-5. Adult males and females are very similar in appearance and are hard to distinguish from one another. Colorado Potato Beetles are often confused with the False Potato Beetle (Leptinotarsa juncta) but can be distinguished because of a difference in color on the center of the elytra. The False Potato Beetle has a brown stripe on the center of the elytra rather than the white one that the Colorado Potato Beetle possesses.
Leptinotarsa decemlineata adults (above left and right). (Copyright by David Cappaert: http://www.insectimages.org/search/action.cfm?q=Colorado%20Potato%20Beetle)
Female Leptinotarsa decemlineata laying eggs (above left) and Leptinotarsa decemlineata clutch. (From: http://growit.umd.edu/plantandpestproblems/Colorado%20Potato%20Beetle.cfm. Copyright by Whitney Cranshaw: http://www.insectimages.org/search/action.cfm?q=Colorado%20Potato%20Beetle)
Adult Natural History: Colorado Potato Beetles are voracious plant pests and feared by professional horticulturists and hobby gardeners alike. Colorado Potato Beetles feed on crops like potatoes, eggplants, and tomatoes but will feed on any solanaceous (those belonging to the family Solanaceae) crop. Colorado Potato Beetles have developed resistance to many of the insecticides used by farmers, causing many to turn to natural means of controlling them. Other insects, such as ground beetles, are predators of Colorado Potato Beetle larvae and eggs and is one method of control used in agriculture.
Female Colorado Potato Beetles are very active egg layers, depositing between 700-900 eggs in one lifetime. This fecundity is one of the major reasons that they are such efficient pests. Eggs are typically orange or yellow in color and are laid on the underside of host plant leaves in clutches of about 20-30 eggs. The eggs hatch 4-15 days after being laid and larva emerge and begin to feed of the leaves of the host plant. Larvae go through four instar stages after which they drop to the soil, bury themselves and pupate. If temperature, light and resource availability is good, the new adults may emerge to continue another life cycle. If conditions are poor, the beetles may enter a diapause stage until conditions are more favorable. In one growing season, its is possible to see up to three generations of Colorado Potato Beetles.
As weather changes begin to occur in the late summer, many Colorado Potato Beetles can migrate to the margins of fields and gardens and bury themselves in the soil to overwinter. It is often possible to see Colorado Potato Beetles in every stage of development (eggs, larvae, and adult) during the mid-to-latter part of a growing season.
Larva of the Colorado Potato Beetle (above). (Copyright by Whitney Cranshaw: http://www.insectimages.org/search/action.cfm?q=Colorado%20Potato%20Beetle)
Colorado Potato Beetle distribution worldwide. (Map by: http://en.wikipedia.org/wiki/Colorado_potato_beetle)
Distribution: The species is widely distributed in Kansas. Currently, the Colorado Potato Beetle can be found all across North America, Europe, and Northern Asia. In European nations, the Colorado Potato Beetle is considered a quarantine pest in countries like England, Ireland, and Sweden.
Habitat: Colorado Potato Beetles are a terrestrial species and can be found in gardens and agricultural fields alike. Much of the Colorado Potato Beetle's life is spent around its host plants, either on the plant itself or in the soil (during both the pupal stage and overwintering periods) around it.
Diet: Both the adult and larval stages of the Colorado Potato Beetle feed on host plants (potatoes, tomatoes, etc.). The only time it does not feed is during its time as a prepupae, when it prepares to drop to the soil, bury itself and prepare for adulthood.
Conservation Status: Very Stable
Colorado Potato Beetle (Chrysomelidae: Leptinotarsa decemlineata)
How To Grow Potatoes : How to Stop Potato Beetles
Hands on Gardening - Colorado Potato Beetle
Top Vegetable Pests - Colorado Potato Beetle: http://growit.umd.edu/plantandpestproblems/Colorado%20Potato%20Beetle.cfm
University of Minnesota: VegEdge: http://www.vegedge.umn.edu/vegpest/cpb.htm
Colorado Potato Beetle: http://en.wikipedia.org/wiki/Colorado_potato_beetle
American Insects: http://www.americaninsects.net/b/chrysomelidae.html
Bug Guide: http://bugguide.net/node/view/2706
Bradley, F.M. 2007. Rodale's Vegetable Garden Problem Solver: The Best and Latest Advice for Beating Pests, Diseases, and Weeds and Staying a Step Ahead of Trouble in the Garden, Rodale, New York, NY.
Marshall, S.A. 2006. Insects : Their Natural History and Diversity: With a Photographic Guide to Insects of Eastern North America. Firefly Books, Buffalo, NY.
Salsbury, G. A. and S. White. 2000. Insects in Kansas, Third edition. Kansas Department of Agriculture, Topeka, KS.
Submitted By Timothy Eberl, November 2011.