The tissue between the leaf veins is eaten, giving the leaves a lacelike appearance. Copper-colored beetles about 1/4 inch long feed on the undersides of the skeletonized leaves. The beetles have sixteen 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.
Apply a garden insecticide labeled for Mexican bean beetle when the adults first appear, following the instructions. Remove and destroy all plant debris after the harvest to reduce overwintering spots for adults.