The apple maggot larva is a typical fly larva. It is cylindrical, tapering from a blunt posterior to a pointed head, and has no legs. The mature larva is creamy white except for two dark mouth hooks and is 1/4 to 3/8 inch (6 to 9 mm) long The larva tunnels through apple flesh and can be distinguished from other insect larvae found in apples by its lack of a distinct head capsule.
The apple maggot fly is about the size of a common housefly. Its body is black, its eyes are dark red, and the thorax and abdomen have distinctive white or cream bands. The male has a blunt abdomen with three white lines, while the female's more pointed abdomen has four white stripes.
Damage: Apple maggot feeds on fruit and if left unchecked can damage almost all the fruit on infested trees. Even small numbers of apple maggot can heavily damage apple crops. When eggs are deposited under the fruit skin the cells surrounding the puncture are damaged. As the apple grows it becomes dimpled and lumpy. This is more evident in apples attacked early in the season. Feeding by the larvae leaves brown trails in the apple flesh. When many larvae feed on a fruit, the flesh often turns mushy and the apple drops early. In hard, later maturing apples, internal breakdown may not be apparent until after the apple drops.