The apple maggot is a major problem for the home apple grower. The larvae or maggots then tunnel through the fruit leaving brown trails or streaking. When the infested fruit falls to the ground, the mature maggot crawls out of it and burrows into the ground, where it will pupate over the winter. Adults begin to emerge in July and will lay eggs right into September, and the cycle starts all over again.
Chemical control can be difficult because of the long emergence and egg laying periods.
Hanging red balls in the tree, covered with a sticky substance called tanglefoot, will attract and trap the adult flies before they have a chance to lay their eggs in the apples. Hang five traps in an average size tree before the first of July. If chemical control is desired, using the traps will help with the timing of spraying. Make the first spray one week after catching the first fly, and make additional sprays as long as flies are still caught in the trap. Traps are very useful indicators of when and how long to keep spraying, because of the prolonged emergence period.