The most serious pest of home-grown apples in Connecticut is the apple maggot or, as it is sometimes called, the railroad worm. This insect is responsible for the brown, rotten streaks found in fruit that otherwise look sound and pest free at harvest.
Infested fruit has a tendency to drop prematurely.
Apple varieties most susceptible to maggot attack are Wealthy, Cortland, Gravenstein, Red and Golden Delicious and early sweet or subacid varieties. However, the maggot will attack any variety. The fruit of early ripening varieties and of severely infested late ripening varieties are usually quite distorted. It is black except for white bands on the abdomen, three on the male and four on the female, and a white spot on the upper surface of the body near the point where the wings attach. The wings are transparent with conspicuous black markings.