Apple maggot is the wormlike larva (young) of the apple fly. Apple maggots sometimes do serious damage to apple crops. These insects are also called railroad worms because they make long, winding trails under the apple skin. Apple maggots are especially harmful in New England and northern New York.
The adult fly is a kind of fruit fly. It is slightly smaller than the common house fly and has wings marked with four black bands. Eight to ten days after appearing in midsummer, the female fly begins laying eggs just under the skin of apples. Sometimes as many as 15 eggs are laid in one apple. The maggots that hatch burrow through the flesh of the apple, leaving rusty streaks in it. After feeding from four to six weeks, the maggots drop to the ground and enter the soil. They change to the pupal stage there and stay all winter. They emerge the following summer as adult flies.
Scientists have discovered that apple maggots can be controlled by hanging sticky traps of yellow panels or red spheres in the apple orchard. Adult flies are attracted to the shape and color of these traps, and they become entangled and die in the special adhesive.