Jaime:

Most larval problems result from insects (especially moths) laying eggs on the surface of young, developing fruits. The eggs hatch quickly into larvae that burrow into the fruit. The easiest time for them to do this is when the fruits are in the early stages of development, with tender skins. Look carefully around the surface of larval-infested fruits and you will nearly always find the site of insect penetration. The entire objective of spraying or bagging fruit is to prevent insects from laying eggs on the young fruits.

There are some insects, such as the oriental fruit moth, whose larvae are capable of burrowing into the fruit through the stem, leaving no signs on the skin, but this is the exception to the rule and is a relatively rare occurrence.

Don Yellman, Great Falls, VA

Perhaps the most common in your region is the codling moth. If so, the larva burrows in either from the side or the blossom end, then yucks up the core area.

If that's not what you see, please explain.

I feel sure you have the Codling moth attacking your Apples ans Pears. Standard practice calls for insecticide sprays at the right TIME to prevent this damage. Talk to your county agricultural agent for the correct time and frequency to spray in your area. Al