If you would like to not have spots on your apples and leave the birds and the bees this article may be just what you’re looking for. Apple Maggot, Rhagoletis pommonella, is a small fly that infests a variety of hosts including crab apple, apples, plum, hawthorn, and occasionally apricots. It has a wide range from North Eastern United States through to Southern Manitoba, Canada
The spots on your apples are created when the female of the species punctures the skin of the fruit laying her eggs. The eggs then hatch and burrow though the apples causing the characteristic traces or brown discolored tunnels in the flesh of the fruit. The plant often responds by dropping infected fruit. Once the fruit is dropped the larvae emerge and pupate in the soil under the host tree. Some fruit remains on the host until fall and larvae develop at a slower pace in these fruits. This leads to a long period of emergence for adults in t the following spring.
Adults emerge the following spring just after the apples have finished blooming and continue to emerge for the next two months. The insects are small flies, slightly smaller than a house fly with black bodies and distinctive black bands on their clear wings. They emerge sexually immature and take a week to 10 days to fully develop. While maturing they feed on honeydew secreted by aphids. Once mature they congregate and mate on fruit.
The female lays as many as 300 eggs in her 30 day life span.
Control of this pest is difficult due to the long period of adult emergence. Chemical controls can be effective if applied at the very end of the flowering period and every 10 days thereafter until the adults are no longer emerging. Time applications to begin after flowers start to loose petals and you will have minimal impact on pollinators such as bees. Horticultural oils can reduce the population of aphids and limit food sources for immature adults. Bright red plastic sticky apples and yellow paper sticky traps can be used to scout for the emergence of adults. Culturally, prompt removal of all dropped apples throughout the season helps to break the life cycle. Dropped apples should be disposed of sanitarily off site. Removing alternate hosts in wild adjacent areas will also help to reduce populations.
If you have questions about apple maggot contact your I.S.A. Certified Arborist to see if you have this damaging plant pest.
I.S.A Certified Arborists are industry recognized experts in plant insect and diseases control.