Beech tree leaves problem

Asked September 3, 2015, 4:12 PM EDT

I own property south of Denton, on the east shore of the Choptank River in Caroline County. We have about 3 acres of woods with a wide variety of trees, and the woods is very mature. We probably have at least 20 beech trees, some mature, some young, mixed among the other trees. All of the beech trees have a problem with their leaves. I noticed this near the end of last summer. Where the leaves overlap they are browning and stuck together. The leaves have had this problem all of this summer. Everything else in the woods seems to be in good condition, normal growth and decay. I've searched for an identification of the problem, but am not finding it. The bark looks normal, it's just the leaves. Recently, while kayaking, I noticed that the beech trees along the shores of Watts Creek, up river from our property, have the same problem.

Caroline County Maryland

3 Responses

This appears to be the feeding injury caused by a leafminer (which are the larval stage of beetles). We can't positively say which one, based on the photos.

Because the damage is occurring late in the growing season and the trees have had plenty of time to carry on photosynthesis and store nutrients, the leafminer is unlikely to be doing significant injury to the trees.

The willow flea weevil (Rhynchaenus rufipes) makes similar damage. Another possibility would be a leafminer that feeds exclusively on beech--Brachys aeruginosus. If you can send us photos of the larva by cutting open the mine, we may be able to be more specific.

The bottom line is that the trees seem to be tolerating the insect. If you have never noticed the problem until last year, the population of the insect may be fluctuating and be high because of recent weather conditions. This suggests that its number will, eventually, also go down.

ECN

Thank you very much and that totally makes sense. The larva are not there now (damage began earlier in the summer), at least that I can tell - just granule "waste" it looks like. But, it is likely that it is brachys aeruginosus because it is only occurring with the beech trees and we have a great variety of trees in the woods. I did suspect that it was related to a greater amount of moisture as damage is where the leaves overlap, as if the leaves had not had time to dry out before the insects settled in. So, we will see what happens next summer!