A: Fortunately, not everything that happens in the yard necessarily needs you to DO something right now.
The crape myrtles are simply covered in spiders, hunting other insects. Unless you see white dots all up and down the plant’s branches (scale), this is the time of year we get a lot more laissez-faire about sucking pests on the leaves of deciduous trees and shrubs! Even if you do have a minor insect pest (such as aphids) on your crape myrtles, we don’t recommend any sort of spray. If you sprayed the crape, the leaves would start dropping in the next four to six weeks. If you don’t, you’ll achieve the exact same result. New growth this spring will be healthy and undamaged. Treatment with a systemic drench insecticide when the leaves first emerge next year will head off new issues before they start.
Many shade and ornamental trees have minor discoloration, fungal spots, or leaves which had been damaged by insects or drought stress during the year. Cedar elms, bur oaks, live oaks, Shumard red oaks, and redbuds are the plants we’re most often asked to look at which have these issues, and for all the trees named, the correct thing to do is generally nothing. Just make sure you’ve fertilized the trees for fall and call it good for now. Trees with minor fungal spot diseases such as live oaks with oak blister may benefit from being pruned during the winter to provide better air flow through their canopies, and most of the insect pests that discolor leaves would be best treated next year.
Burton specializes in diagnosing and solving plant problems. If you have a question for Burton, please email him at burton@covingtonnursery.com and include photos showing the problem.