Master Gardener Valois Pearce advises how to identify problems with pecans. 1. Look for webworms. One control is to cut the branch off if you can. You can break the web with a strong blast of water. 2. Shiny leaves indicate there may be a problem with Aphids. 3. Check for Pecan-nut Casebearer. Should you decide to use insecticide for any of these problems, please check with your local county extension office to confirm spray dates. Even with these precautions trees normally do not give a hundred percent yield. Its normal for a tree to produce hollow shells or some shriveled nuts. This is caused by the tree having a heavy load of nuts and shedding some of the load.