Plum curculio larva
Michigan State University
Size: Up to 1/4 inch long
Where/When: Apple and plum; also apricot, pears, peach, cherry, and crabapple are hosts. The larva appears in June and is active for a period of about 2 weeks.
Significance: Feeding causes scarring or lumpiness on fruits. The fruit is damaged internally by the burrowing larva causing premature fruit drop.