Colorado Potato Beetle Location
The Colorado Potato Beetle is a native, and is so common that it is referred to as simply the “Potato Bug.” Found in the Rocky Mountains feeding on Buffalo Bur about 1923, it did not become abundant until the potato was introduced into its territory. Then it spread eastward from potato patch to potato patch, averaging 85 miles a year, until it reached the Atlantic Coast and invaded Europe.
Although potato is its preferred food, this beetle will eat almost anything available, especially tomato, eggplant, tobacco, pepper, ground cherry, thorn apple, jimson weed, henbane, and thistle.
Colorado Potato Beetle Appearance and Habits
Adults spend the winter buried 8 to 10 inches deep in the soil, emerging in time to feed on the first foliage of early potatoes. They are wide, convex beetles, 1/2″ long, with alternating black and yellow stripes. Females lay up to 20 batches each of orange-yellow eggs in groups on the underside of the leaves, over 4 to 5 weeks. The eggs hatch into humpbacked, purplish-red larvae, with 2 rows of black dots along each side. These larvae eat voraciously, often entirely consuming the leaves. When full-grown they descend into a spherical cell in the ground, transform to a yellowish pupa, and in 5 to 10 days new adults emerge to feed and lay eggs for the second generation.
How to Manage Colorado Potato Beetles
Grow potatoes above ground! Drop potato seeds on 3″ of sod or leaf cover and cover with straw.
Plant natural beetle repellents nearby: flax, horseradish, garlic, eggplant, snap beans, nightshade.
Handpick the beetles and crush the eggs.
Dust the tops of potato leaves with wheat bran. The beetles will eat it and bloat up until they die.
Ladybugs and toads eat beetles.
Spray with basil water.
Spray foliage thoroughly with lead or calcium arsenate, or cryolite, whenever beetles or larvae are present. Either arsenical may be combined with Bordeaux mixture for the control of blight, but cryolite may be used only with a fixed copper free from lime.