Apple maggots are the scourge of cultivated apples but will also attack plums, apricots, pears, cherries, and hawthorns.
Common throughout most of North America, particularly eastern United States and Canada, as well as northern California.
Adult apple maggots are about ¼ inch long - slightly smaller than a housefly. They sport conspicuous black bands on their transparent wings, a prominent white spot where the thorax joins the abdomen, and white stripes on the abdomen itself (3 for the male and 4 for the female).
The larvae are white or yellowish tapered maggots slightly smaller than those of a house fly. The maggots are about ¼ inch long and taper towards the head.
- Apple maggots spend winter in the soil as a pupa. They emerge from the ground around late June/early July, continuing through most of the summer.
- Pupae may remain inactive, appearing in the second year.
- After emerging, adult apple maggots feed for 7 to 10 days, after which they start mating. Females lay eggs under the skin of the host fruit.
- A single female can lay up to 300-500 eggs during her life, which can last 30 or more days.
- Eggs hatch within 3-10 days, depending on the climate.
- The larvae or maggots feed while tunneling through the flesh of their host. Larvae generally complete development in about 2 to 4 weeks; however, climate and fruit hardness influence the growth rate. Some can take three or more months for harder winter variety hosts. Fully grown larvae leave the fruit and then enter the soil to pupate.
- Most apple maggot pupae remain in the ground for one winter. A few may stay there for two or more years.
Damage and Detection
- Injury to fruit is caused both by the adult apple maggot and its larvae progeny.
- As the female apple maggot lays eggs in the fruit, the surface becomes pitted or dimpled. When hatched, the larvae tunnel throughout the fruit, creating winding tunnels – the fruit's pulp begins to break down, discolor, rot, and eventually drop to the ground.
- Fruit slightly infested may show no external indication of the underlying maggots and damage they have wrecked until the fruit is opened.
- Heavily infested early varieties of fruit will be reduced to brown rotten masses filled with fly larvae.
Prevention and Control
Maintain a clean garden
Be fastidious about picking up and removing any apples that have fallen to the ground. Do not compost in your yard.
Red Sphere Apple traps
Sticky traps capture apple maggot females that attempt to lay eggs on the fruit and can greatly reduce damage. Traps should be placed in the canopy when trees are done blooming. Hang the apple traps high in the brightest areas of the tree, about 6-7 feet (180-210 cm) from the ground. Set out one trap for 150 apples.
Beneficial insects are worm-like, microscopic parasites that hunt, penetrate and kill the pupal stage of this pest. For the best results, use in the early spring or fall around the base of trees, out to the drip line. One application will work for 18 months.
Apply clay in a visible layer to all surfaces of trees – it prevents apple maggot flies (and other insects) from laying eggs in the apples. It also has a positive result on fungal diseases like fire blight, flyspeck, and sooty blotch.
As a last resort, botanical insecticides could be used. Derived from plants with insecticidal properties, these natural pesticides are not as harmful as synthetic chemicals. They also break down more quickly in the environment.
Randy Bjorklund, Imageman, Shutterstock
While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.