Source: Whitney Cranshaw, Colorado State University, Bugwood.org
Common Name: Colorado Potato Beetle
Latin Name: Leptinotarsa decemlineata
Main Host(s): Potato, eggplant, tomato
Colorado Potato Beetle (CPB), Leptinotarsa decemlineata has long been a major pest of potato. In addition to potato, the pest also feeds on eggplant and tomato. It can be found in most potato growing regions in the U.S., Europe, as well as some parts of Asia.
Adult beetles emerge in the spring and they move rapidly by walking or flying to a suitable host plant for feeding, mating and egg laying. The beetles have a life span of 4-5 weeks, which includes a lengthy egg laying period of several weeks. Both adults and larvae of various ages can be found on their host plant. Up to three generations per year are possible depending on the climate. Summer generations have a pupal stage of 5-10 days in the soil while shorter day length will trigger the fall generation to pupate for overwintering.
The female of this species deposits hundreds of orange-yellow eggs in clusters of 30-40 eggs on the underside of leaves. The eggs hatch in 4-10 days depending on temperature, followed by four larval instars over a 21-day duration. All life stages can easily be detected and indentified.
Both the immature and adult stages of this beetle can be present at the same time and since the older larvae and the adults are vigorous feeders, the population can do considerable damage to host plant foliage. In potato, defoliation of up to 15-20% can be tolerated, but CPB populations should be kept low throughout the season.
This pest has developed resistance to virtually every conventional insecticide that growers have tried. The list includes organophosphates, carbamates, pyrethroids and since 2006 the first cases of resistance to neonicotinoids are known. Novodor® (Bacillus thuringiensis subspecies tenebrionis) is a logical choice for CPB control because the Bt mode of action is different from any conventional insecticide and no cross-resistance has ever been reported. Novodor is a highly specific, highly effective product for controlling CPB. In particular, it is one of very few options for CPB control for growers of organic potatoes.