Colorado Potato Beetle (CPB) -
Helen Atthowe - Missoula County Extension Whitney Cranshaw, Colorado State University, www.ipmimages.org
DESCRIPTION: Adults are hard-shelled, with alternating black and yellow stripes, they are 3/8 inch long, and are frequently found on young plants, especially in the spring. Larvae are soft-bodied, humpbacked, pinkish-red grubs with two rows of black spots down each side of the body.
LIFE CYCLE: CPB overwinter as adults in plant debris. They emerge in mid-spring and lay bright orange eggs on the undersides of host plant leaves. Larvae hatch, feed on leaf undersides and then move to upper leaf surfaces. There are several generations per season.
Cultural: Deep straw mulch around susceptible solanaceous plants has been shown to suppress the first generation of Colorado potato beetle adults and larvae in late spring/summer.
Research with living mulches of rye/vetch in row middles mowed and left to dry, must cover young plants. As the plants grow above the mulch level, they are susceptible to second generation Colorado potato beetle damage .
Biological: Bt-San Diego or Bt-tenebrionis gave nearly as good results as the insecticide Temik, but without killing beneficial insects.(USDA study in WA state). Bt-tenebrionis was most effective on newly-hatched larvae. See Bacillus thuringiensis.
In the same WA study, control using Beauveria bassiana was inadequate until potato plants grew enough to cover bare soil in the row. Beauveria, the biological control fungus, requires high humidity for germination and infection.
The two-spotted stinkbug, Perillus bioculatus, is a good predator of Colorado potato beetle. Five consecutive releases of the bugs, starting when eggs were first present, maintained plots in New Brunswick, Canada, virtually free from Colorado potato beetle.
This stinkbug has been reported feeding on Colorado Potato Beetle in Western Montana!