Life cycle of the larvae

Adult females are highly fertile and can lay between 300 and 500 eggs. The egg masses are bright yellow to orange and are usually found in clusters of ten to thirty eggs on the underside of leaves. The larvae hatch from the eggs after 4-9 days, depending on the ambient temperature. The larvae molt three times in succession before pupating. The first-stage larvae are blackish-brown in color and very small, about the size of a pinhead. Once hatched, the first-stage larvae prefer to feed on newly grown foliage at the crown of the plant. Due to their small size, the damage is minimal. The second-stage larvae turn a deep orange-red color and their leaf consumption doubles compared to the first stages. Third and fourth stages have bright red abdomens with black heads and legs. The sides of these stages are lined with a row of black spots. The fourth stage is often larger than a pea (~10 mm). The last two larval stages eat more and more leaves and cause the most economic damage to nightshade crops. After completing four stages in 2-3 weeks, the larvae return to the ground to pupate. Within 10-14 days, the second generation of adult beetles emerges.

At an optimal temperature of 28 degrees, the Colorado potato beetle can develop from egg to adult beetle in 21 days. Under less favorable conditions, this development can take 6 to 7 weeks.Adult beetles that emerge after mid-August usually feed for a few days and then burrow back into the ground or fly to the edges of forests to enter diapause for the winter.