The apple curculio is causing severe losses in a number of Iowa apple orchards and is not being controlled by spraying. The injury is caused by the feeding of the adult curculios on the fruit. The insect has a long beak with small jaws at the tip with which it chews a hole thru the skin of the apple and hollows out a large cavity below without increasing the size of the opening.
This insect shows a peculiar preference for certain varieties, notably the Ben Davis and Delicious, while some varieties such as the Northwestern Greening are practically free from attack.
Fulton, B. B., "The Control of the Apple Curculio by Hogs" (1929). Circular. Paper 117.