4 (1 = rare 5 = annual)

4 (1 = very little damage 5 = plants killed)

Potato, pepper, tomato, and eggplant.

Vegetable

• Eggplant (Solanum melongena L.)
• Pepper (Capsicum annum L. var. annum)
• Potato (Solanum tuberosum)
• Tomato (Lycopersicon esculentum)

The adult Colorado potato beetle is about 1/2 inch long and yellow with brown stripes. The larva is orange to red, with black spots, and can be 1/2 inch long when full grown. Both the larva and adult eat the leaf margins and entire leaves of potato, pepper, tomato, and eggplant.

Colorado potato beetles overwinter as adults in the soil.They become active in the spring as early potato plants emerge. They feed on the young potato plants, and they lay bright orange eggs in clusters on the stems and foliage. Larvae also feed on foliage. Typically, two to three generations develop each summer in Illinois.

Thresholds used in commercialpotato production give some idea of what constitutes an infestation that needs to be controlled in gardens as well. On young potato plants in the spring, control is probably warranted if feeding by adult beetles or larvae results in more than 20 to 30 percent defoliation (20 to 30 percent of theplant's leaf area is lost); this usually happens when more than 2 to 3 adult beetles are feeding on each plant.In the summer, when potato plants are blooming, some yield reduction is likely if defoliation exceeds 5 to 10 percent; this usually occurs when infestations exceed 5 larvae or 3-5 adults per plant.

Natural enemies rarely keep Colorado potato beetle in check, so where infestations occur, hand-picking and application of insecticides are the most common approaches to controlling this insect in home gardens. In addition to conventional insecticides, microbialinsecticides that contain Bacillus thuringiensis tenebrionis can be used to kill Colorado potato beetle larvae. These microbial insecticides kill the target pest without killing other insects. Populations of Colorado potato beetle are resistant to one or more insecticides insome areas. If a registered insecticide fails to give control, switch to another insecticide in a different class. Do NOT retreat using a higher rate of the same insecticide.

Home, Yard & Garden Pest Guide
The Home, Yard & Garden Pest Guide (C1391) provides is written for homeowners and other residents and provides nonchemical and current chemical recommendations for controlling pests associated with trees, shrubs, turf, flowers, groundcovers, vegetables, fruit, and houses. In addition, you'll find detailed information about integrated pest management, pesticide safety, and pesticide application and calibration techniques. This publication may be purchased at your local University of Illinois Extension Unit office, or by calling 800-345-6087, or by placing an order online (search for "C1391").
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U of IL - Distance Diagnosis through Digital Imaging
A free plant, weed, insect and disease identification service available through your local University of Illinois Extension office. Center Educators or State Specialists review & respond to information and digital images submitted by local Extension office personnel. Some samples may require further examination or culture work (nominal fee involved) at the U of IL Plant Clinic.
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U of IL - Plant Clinic
Services include plant and insect identification, diagnosis of disease, insect, weed and chemical injury (chemical injury on field crops only), nematode assays, and help with nutrient related problems, as well as recommendations involving these diagnoses. Microscopic examinations, laboratory culturing, virus assays, and nematode assays are some of the techniques used in the clinic.
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