NDSU Extension Service - Burleigh County


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Apple Maggot Fruit Damage

Apple Maggots, one of the most destructive pest of apples has hit the area, causing this year's harvest to be disappointing. The tiny maggots create tunnels or "railroad tracks" in fruit and have a bump outer appearance. The second injury occurs as the maggots tunnel through the flesh. As a result, the pulp breaks down, discolors, and starts to rot.

In most cases there is only one generation of apple maggot a year. The female will lay her eggs singly beneath the skin of the fruit and the larvae will hatch 3-7 days later and tunnel into the fruit pulp.Apple Maggot Pic

The larvae will stay in the fruit until they reach maturity at that time they make an exit hole in the skin of the fruit and drop to the ground and enter the soil to a depth of 2-5 cm where pupation occurs.

The pupae will stay dormant over winter where they may persist for several years or emerge in late June or July as an adult. As the flies mature and mate they respond to fruit shape and fruit odor.  After mating, a single female fly is capable of laying more than 200 eggs in her lifetime. Adults usually die after 3-4 weeks.

You can use a sticky red sphere trap as a way of monitoring apple maggot presence in your orchard, so that you can spray an insecticide at the right time to control the flies. Many other insects will also get stuck, some of them small flies with similar wing markings, so learning to positively identify the apple maggot fly is very important. Check the trap frequently.

Effective insecticides available for apple maggot control are esfenvalerate  (conquer), carbaryl (sevin), and spinosad (organic insecticide).

It’s important to observe the pre-harvest interval, or the "days to harvest,” i.e. the interval between pesticide application and harvest. Any fruit picked sooner than this should not be eaten and should be discarded. In some cases, this interval could be as long as three weeks.

Read the label of the particular insecticide you are using for this information. Fortunately, apple maggot adults are found in smaller numbers as the season progresses, and you should be able to stop spraying sometime in August.

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