Apple maggot adults look like small house flies with striped wings, though they are really fruit flies. They primarily fly and lay their eggs in July and August in Washington. Apple maggot females make a tiny puncture in the apple skin and lay their eggs just under the surface. While the initial damage is easily overlooked, the damage eventually leads to dimpling of the fruit surface.
In only 3-7 days, apple maggot larvae eggs hatch and tiny apple maggots emerge. The leggless maggots are about 1/16 of an inch long and a creamy white color but grow to about 1/4 of an inch long at maturity. The maggots eat and tunnel their way through the fruit, leaving brown trails behind.
When apple maggots are mature, they exit the fruit and drop to the ground. They overwinter as pupae in the soil, emerging the next summer as adults, starting the cycle over again.