The Potato bug or Colorado potato beetle is a black and yellow-striped beetle, and is the most serious insect threat to potatoes. Both the adult beetle and larvae feed on potato leaves. Their feasting will greatly reduce potato yields and kill off plants. They also feed on tomato, ground cherry, eggplant, and pepper plants.
The adults overwinter in the soil and emerge in the spring to begin feeding on weeds and early potatoes, they also penetrate the soil and attack emerging foliage. They lay their orange-yellow eggs in batches of 20 -30 on the undersides of the leaves.
A female can lay over 500 eggs over a two month period. Eggs hatch in less than 2 weeks and the larvae immediately begin feasting on potato plants.
The Colorado potato beetle have two rows of black spots on either side and are some what humpbacked. The larval stage lasts two to three weeks after which they burrow into the ground to pupate. In five to 10 days, adult beetles emerge. The Colorado potato beetle can go from egg to adult in three weeks. The newly emerged adults feed for several days before egg laying begins anew. There are up to three generation annually. Foliar pesticide sprays should be made just after the majority of eggs have hatched, before serious plant damage can happen.
Control and Management Tactics
Handpicking is not always feasible in larger gardens. In small gardens, handpicking is generally effective. Destroy adults and larvae, New adult beetles may eventually migrate to your garden, so be sure to check your plants on a regular basis.
Beneficial insects such as , predatory stink bugs, Lady Bugs and parasitic wasps will help to control Colorado potato beetle populations to some extent. Birds will too.
Insecticides available to home gardeners are not always effective due to widespread insecticide resistance built up by Colorado potato beetle populations. An orchestrated combination of pest cotrol tactics will help to keep Colorado potato beetle populations under control.
Bacillus thuringiensis a natural bacteria is highly effective against the Colorado Potato Beetle. It will control early stages of the Colorado potato beetle and larvae. It is not as effective against adults. BT must applied as soon as possible, when the beetles or larvae are still young.
Pyrethrin an eco-friendly pesticide, is effective against the adults, and not very much resistance to this natural toxin has been reported. Neem and Spinosad are also effective against Colorado potato beetles, and there is negligible resistance.