Q. Why do apple trees drop their fruit early? We have an old apple tree on our property that produces pocked, rotten apples. Is there way we can help the tree produce edible fruit?

A. Some fruit trees will naturally thin themselves by dropping excess fruit prematurely. Often, a period of stress (a long, hot summer with very little rain) will cause a tree to abort its fruit in order to conserve energy. Apple trees require deep watering during drought. Lack of pollination can result in pea-size fruit that falls off prematurely.

To encourage your fruit trees to yield the maximum amount of healthy fruit, they must be part of a regular spray program that includes dormant oil as well as insecticide and fungicide treatments. Whether you choose to use synthetic chemical products or the less toxic, more environmentally friendly ones, adherence to a strict schedule is important. The first treatment, applied in early March, consists of a dormant oil sprayed thoroughly over the tree's trunk and branches. This petroleum-based product is applied before the tree begins active growth, but only if the temperature is 40 degrees with no danger of freezing or rain for the next 24 hours. Dormant oils are often used on other deciduous trees since they are quite effective in controlling overwintering insects and their eggs.