Cooperative Extension: Potatoes

Colorado Potato Beetle

Adult Colorado Potato Beetle

The adult form of the Colorado potato beetle is about 3/8″ long and 1/4″ wide. The wing covers have characteristic yellow and black stripes.

In Maine, only the adult form of this insect over-winters.

The economic threshold for adult beetles: Average of 25 adults per 50 plants surveyed.

Adults are capable of creating significant feeding damage, especially on small potato plants.

Colorado Potato Beetle Larvae

Colorado potato beetle larvae are orange/red in color with distinctive black spots along the side. This form of the Colorado potato beetle is capable of significant feeding damage.

The economic threshold for Colorado potato beetle larvae:

• Small larvae: 200 per 50 plants.
• Large larvae: 75 per 50 plants.

Colorado Potato Beetle Larvae and Eggs

Typically very small Colorado potato beetle larvae will feed on the tender new growth of the plant. Larvae will feed and grow rapidly.

Colorado potato beetle eggs are yellowish-orange, usually laid on the underside of a leaflet. Each adult female is capable of laying up to 500 eggs. Egg masses are usually laid with 15-40 eggs per egg mass.