The larval form of the dipteran fly Rhagoletis pomonella is known as the apple maggot: a pest of apple orchards. It is a species native to North America, thought to have diverged into two separate races (incipient species) in the early 1800s, when apples were introduced into the United States. The pest race feeds primarily on apples (and sometimes alternative fruiting hosts including cherry and plum), whereas the other race primarily uses Hawthorns (Crataegus sp.). The adult form of this insect is about 5 mm (0.2 inch) long, slightly smaller than a housefly, with a white dot on its thorax and a characteristic black banding shaped like an "F" on its wings. After female flies lay eggs just under the skin of the fruit, the small white/yellow larva hatch out and burrow in the fruit’s flesh, feeding on the juices. When fully grown (about 125 mm long), the maggot chews out of the fruit and drops to the ground to pupate just under the soil, usually remaining a pupae for two winters before hatching out as an adult fly. Chemicals can be used to treat the adult fly (by spraying the tree) or targeted at the pupae, by chemically treating the soil. The maggot stage has many enemies, including several braconid wasps: Utetes canaliculatus, Diachasmimorpha mellea, and Diachasma alloeum.

Miller, Steele and Smith; Weems and Fasulo 2009; Wikipedia 2011)