COLORADO POTATO BEETLE

a, Adult beetle; b, eggs; c, larvae (or slugs) ; d, pupa (or resting stage). (a, c, and d, about natural size; b, about twice natural size.)

COLORADO POTATO BEETLE

The eggs of the Colorado potato beetle are laid in bunches on the under sides of the leaves. The eggs hatch in 4 to 9 days. The larvae (or slugs) feed on the plant. The larva grows rapidly, passing through four stages, similar in appearance except that each stage is larger than the stage that preceded it.

It becomes full-grown in 10 to 21 days after hatching. It then burrows into the ground and changes to a pupa, or resting stage. After 5 to 10 days the adult beetle emerges from the pupa, crawls up out of the ground, and, after feeding on the plants for a few days, may lay eggs for another brood of larvae.

Control: Dust the foliage thoroughly with a 3 percent DDT dust. Sprays are also effective if applied with a good sprayer that throws a fine mist. To each gallon of water, use 3 level tablespoonfuls of 50 percent DDT wettable powder or 2 level teaspoonfuls of 25 percent DDT emulsion concentrate. To make 100 gallons of spray, use 3 pounds of the 50 percent wettable powder or 2 pounds of the 25 percent DDT emulsion concentrate. If sprays are to be used for disease control, either of these DDT preparations may be added to the fungicidal spray rather than to water, and both materials applied with one operation.

Begin spraying or dusting when the beetles first appear. Spray or dust for the slugs when eggs are hatching, and repeat the treatment as often as necessary.