Problem Identifier Unit Screen//v.w/ RR Template

Problem Identifier Unit Screen//v.w/ RR Template Mexican Bean Beetle

Problem
The tissue between the leaf veins is eaten, giving the leaves a lacelike appearance. Copper-colored beetles about ¼ inch long feed on the undersides of the skeletonized leaves. The beetles have 16 black spots on their backs. Orange to yellow soft-bodied grubs about 1/3 inch long with black-tipped spines on their backs may also be present. Leaves dry up, and the plant may die.

Analysis
(Epilachna varivestis)

This beetle is found throughout the United States. It prefers lima beans, but also feeds on pole and bush beans and cowpeas. Feeding damage by both adults and larvae can reduce pod production. The adult beetles spend the winter in plant debris in the garden and emerge in late spring and early summer. They lay yellow eggs on the undersides of the leaves. Larvae that hatch from these eggs, in early to midsummer, are green at first, gradually turning yellow. There are 1 to 4 generations per year. Frequently, all stages of beetles appear at the same time throughout the season. Hot, dry summers and cold winters reduce the beetle population.

Solution
Apply an insecticide containing carbaryl or diazinon when the adults first appear. Be sure to spray the undersides of the leaves where the insects feed. Early treatments to control the adults may save extra applications later to control the larvae, which are more damaging and harder to control. Remove and destroy all plant debris after the harvest to reduce overwintering spots for adults.

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