| Life Cycle: | The adult Colorado potato beetle first emerges from the soil late May or early June. It is approximately 1 cm long. It has a very distinct set of ten lengthwise black lines interspaced by the yellow background on its wing covers. Its head is orange with black spots. Its body is round and humped back. When the potato beetle emerges it immediately begins feeding on host weeds or the leaves of early planted potato crops. Female potato bugs can lay up to 500 eggs over a 4-5 week period. The eggs can be found on the underside of the host plant's leaves in clusters of thirty. They are yellow to orange in colour. The eggs hatch in 4-9 days also over a 4-5 week period. The larva have a milky red appearance, are humped back and have a row of black dots along each side. The larvae feed over a 2-3 week period after which they enter the soil to pupate. Pupation lasts for 1-2 weeks after which the adult emerges from the soil. It is not unusual for a second generation of larvae to emerge, but generally the mid-season adults continue to feed in preparation for overwintering in the soil. |
| Host: | Members of the solanaceae family are the only hosts of the Colorado potato beetle. Within the family it has a preference for potato plants. Solanaceous weeds such as climbing nightshade and wild tomato are also hosts. |
| Bio Region: | Throughout North America where potatoes are grown with the exception of Newfoundland. |
| Damage: | Both the adult and the larvae chew on the leaves of the host plant. In severe infestations the plant can be defoliated and die. Any defoliation can impede the potato plant's growth and ability to feed the tubers. This is particularly true while the plant is in bloom. |
| Management: | Crop rotation is effective at reducing or delaying damage from potato bugs. It is also possible to prevent field access to the bug by surrounding fields with a plastic-lined trench. In smaller operations, row covers coupled with rotation is very effective; however, row covers must be removed when the plants are in bloom. Hand picking is also a tool for the small scale producer as is planting late in June. |
| Controls: | There are formulations of both rotenone and spinosad that can be used with restrictions on organic farms in Canada. Bacillus thuringiensis (Berliner) is also registered for use in Canada; however, this strain has no formulation that is approved in organic systems. The Colorado potato beetle quickly develops resistance to insecticides. Reliance on organically approved pesticides may not prove effective in the long-term. The use of natural predators such as the lady beetle and other commercially available ground beetles does not have an appeciable impact on any sizeable population of Colorado potato beetles. |
