Striped yellow and black beetles and brick-red larvae cause this damage. Clusters of yellow eggs are found on the undersides of the leaves. Colorado Potato Beetles. This Beetle is not a problem in western coastal areas. Leaves have numerous small, round holes, causing a shot-hole effect.
Tubers have threadlike tunnels with corky brown tissue.
Spray Methoxychlor or use Sevin on upper and lower surfaces of the leaves. Leaves have circular, black spots. Rings develop and leaves may drop. Not prevalent in coastal areas. Plant early and fertilize.