Q. Every year my apples are infested with apple maggots. Would placing paper bags over the apples as soon as they have set fruit and taping the bags securely to the supporting limbs control them? I also have problems with codling moths. However, I understand that these pests lay their eggs on the blossoms so bags would not help, but I can live with their damage. The maggots, however, ruin the crop.

- J. R., Bellevue, WA

A. "The fruits of apple trees are often ruined by coddling moth larvae and apple maggot. Coddling moth larvae are usually found in the core area of the apple. The adult lays eggs inside apple blossoms. When the fruit forms, the egg hatches into a worm-like larvae.

Apple maggot is the immature form of an adult fly. The fly lays eggs just under the skin of the developing apple. When the eggs hatch, the larvae tunnel throughout the flesh of the apple, leaving rust-colored frass (bug poop). When it's time to leave the apple, the larvae digs an exit hole, spins a web, and pupates in the soil below the tree, where it emerges as an adult some months later.

Control of both these pests is difficult. There are some pheromone traps (sex attractant) available that you can hang in your trees. Many gardeners have success in trapping apple maggots by using red rubber balls (or painting Styrofoam balls red) coated with a sticky substance made for this purpose, and hanging them in the tree. The flies are attracted to the red spheres and try to lay their eggs. They'll be hopelessly stuck if they land. Be sure to pick up and bury any infested or fallen fruit from the tree to prevent a population explosion of either pest.

Bagging the apples is another way to exclude the insects, and while labor-intensive, it is effective."

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Q. We have two apple trees that are over 10 years old and are bearing prolifically. However, the fruit has been gnarly and misshapen for several years. We have sprayed with a fruit spray -- sometimes not as often as recommended. We haven't had any problems with worms -- just the gnarly fruit. Is this a certain kind of fungus? How do we control it?

- A. B., Otter Lake, MI

A. "A number of things can cause misshapen fruit. If the weather is cold and rainy during blossom, incomplete pollination can cause misshapen fruit. Apple scab, a fungal disease, can also cause the fruit to be less than perfect. Feeding from the rosy apple aphid can cause fruits to have a puckered appearance.

If the foliage on the trees looks healthy, I'd guess the misshapen fruit is weather related. If the leaves have spots (beginning as olive-green and then turning brown) it's probably apple scab and early spring applications of lime-sulfur should control it. If you've been spraying with fungicide but not as often as recommended, you're not providing complete protection for your trees. Follow the label directions, spraying at recommended intervals to protect your tree.

Feeding from the rosy apple aphid will cause distorted leaves as well as misshapen fruit. To protect against this pest, use a dormant oil to smother the overwintering eggs.

There are a number of other possible causes; your best bet might be to bring a sample to a local extension office or experienced grower to make a positive ID. You don't want to spray pesticides if you don't need to, and it's best to target your spray to the actual culprit, rather than spraying an "all-purpose" spray."

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