Colorado Potato Beetle [fact sheet]

The Colorado Potato Beetle (CPB) preferred the potato to its host weed and has spread to become a serious pest throughout the US and Eastern Canada. The CPB feeds on the leaves and terminal growth of the nightshade-family plants, such as potato, tomato, and eggplant. The potato, however, is its preferred plant. The above-ground destruction of potato plants can cause severe reduction in tuber size and overall yield.

The Colorado potato beetle (Leptinotarsa decemlineata) became a pest when settlers brought potatoes into the Rocky Mountain area, the native habitat of this beetle. The beetle preferred potatoes to its host weed, and now is a serious pest throughout the U.S. and Eastern Canada.

The Colorado potato beetle feeds on the leaves and terminal growths of such plants as potatoes, tomatoes, and eggplant. Potatoes are the preferred host. The defoliation can cause severe reductions in yield and tuber size.

Description

Colorado potato beetle larvae are up to 1/2" long, hump-backed, and shiny reddish bronze, with two rows of black spots on each side.

The adults are distinctive yellow and black striped beetles. Ten black stripes run along the length of their wing covers. They are convex, about 3/8" long and 1/4" wide. Their spindle-shaped orange-yellow eggs can be found in groups, usually on the underside of leaves.

Life Cycle

The Colorado potato beetle overwinters as an adult in the soil. It emerges early in the spring and mates. The female lays eggs on the underside of host leaves in batches of about 24 over a 4-5 week period. In total, about 500 eggs are laid per female. The eggs hatch within 4-9 days and the larvae begin to feed immediately. They grow through four stages in 2-3 weeks. Then they enter the soil, form a spherical cell, and pupate. The new adults emerge in 5-10 days and the life cycle is repeated through a second generation.

Management

IPM Strategies:

Cultural Practices- This insect can become resistant to pesticides quickly, so it is important to incorporate non-chemical measures into your management program. Examples are planting into a standing stubble, rotating crops, and barriers such as spunbonded row covers, trench traps, and trap crops. If problems are severe, consider growing no potatoes or eggplant at all for one year, to break the pest cycle.

Monitoring - Monitor for damaging populations. *For more information see the New England Vegetable Management Guide.

Biological Control - There are a number of natural enemies that attack Colorado potato beetle eggs or larvae, so it will be important to know if they are present before applying pesticides.

Chemical Control - Colorado potato beetle has developed resistance to many insecticides. Therefore, growers should rotate insecticides between various modes of action, to reduce the likelihood that resistance will develop.

Consult the New England Vegetable Management Guide or your county Agricultural Field Specialist for specific recommendations.

Stop!
Read the label on every pesticide container each time before using the material. Pesticides must be applied only as directed on the label to be in compliance with the law. All pesticides listed in this publication are contingent upon continued registration. Contact the Division of Pesticide Control at (603) 271-3550 to check registration status. Dispose of empty containers safely, according to New Hampshire regulations.
 
Photo credit: Bugwood.org
 
Download the resource to see the complete factsheet.