Apple Maggot - Apple Maggots

Fruit damaged by apple maggots eventually becomes soft and rotten, and cannot be eaten.
Apple Maggot Life Cycle and Damage

Female apple maggot flies deposit eggs singly just below the skin of an apple or other host fruit. When the female lays an egg, a small but visible puncture is made in the fruit which can lead to "dimpling." Eggs are elongate (l/16 inch)* curved, smooth, and white. Depending on temperatures, the eggs hatch after a 3-7 day incubation period.
The tiny cream-colored larvae (maggots) feed in the fruit, passing through three growth stages. Maggots are about 3/8 inches long. The damage caused by the maggot resembles a series of brownish, irregular tunnels called railroading. The tunnels are enlarged by bacterial decay that often follows apple maggot damage. Damaged fruit eventually becomes soft and rotten and cannot be used.

After about 20-30 days in the fruit, the maggots drop to the ground where they bury themselves in the soil. There they change to the pupal stage and spend the rest of the winter. They emerge as adults from July through September. The adults must feed for a period of 7-10 days in order to reach sexual maturity. After this period, they are attracted to fruit, where they mate and the females lay eggs. There is one generation per year. The apple maggot fly is about l/4-3/8 inches long. It has a black abdomen. Females have four white bands on the abdomen. The smaller males have three bands. The wings are clear but are marked with black bands. The apple maggot is closely related to the walnut husk fly, cherry fruit fly, and other picture-wing flies, including the snowberry maggot, an extremely close "look-alike.' Because of their close resemblance to these insects, entomologists must dissect them to confirm their identity.

Control

Since apple maggot renders apples virtually inedible and no completely effective cultural or biological control techniques exist as yet, chemical control becomes essential if this pest has been detected in your fruit. The names of currently recommended spray products can be obtained from your local County Extension office. Since the adult flies are emerging over a long period of time, it is important that applications begin about mid-July and continue at 7-10 day intervals up to the preharvest interval man- dated by the label of the insecticide you choose.

Prepared by Elizabeth Beers, Ph.D., Extension Research Entomologist, WSU Wenatchee; Arthur L. Antonelli, Extension Entomologist, Ph.D.,WSU Puyallup; and Eric LaGasa, M.S., Chief Entomologist, WSDA. Olympia, Washington. Reviewed by Mary Robson, Horiculture Agent, 1996.Link update 04/05/10