Try Trap Crop As Early Warning Device
Black nightshade (Solanum nigrum) or eggplant can be used as a trap crop to spot early infestations of Colorado potato beetles. Locate them in or within 10 to 15 feet of the crop threatened by the beetles. Once the trap crop is heavily infested, you must pull and compost it before it begins to create more pest problems itself. Since eggplant may be one of the crops you want to harvest, plant the trap crop early and the main crop later.
Bran Powder Dusting
Sprinkle plants with wheat bran powder. The beetles eat the bran, it expands inside them, and they explode.
Handpicking
Handpicking makes a sizable dent in the beetle infestation right away. It is best to attend to the very first adults that appear to set back their egg-laying activities. This can be a great task for small children even if you have to pay them so much for each dozen picked.
Barriers
Diatomaceous Earth (D.E.) - Dust the whole plant with D.E. to destroy the larvae. Dusting should progress upward from the ground, covering all stems and leaves, especially the undersides. Apply in the late evening or at night, when beneficial insects are less likely to be on the plants.
Netting or Fleece Cover - Nylon netting, fine screening, or agricultural fleece row covers are all effective barriers that prevent beetles from flying in to lay eggs on the crop's leaves. Lay the barrier material directly on the plants and seal all the edges to the ground. Provide lots of extra material so that the plants don't strain against the covering when they grow larger. Don't use a row cover if you grew infested potatoes in that spot the previous season, or if you have seen beetles in the soil. You will be trapping them on the crop, not keeping them off it.
