Worm-riddled arborvitae (sp)

Asked June 30, 2017, 1:22 PM EDT

Two days ago we had to cut down one of our beautiful arborvitae trees. It was about 5 inches in diameter and was approximately 20 years old. The greens & branches had turned brown gradually over the Spring, starting with he part of the branch closest to the tree. Quite quickly, over about 2 weeks, the branches were brown and the greens curled and yellow throughout the tree. After cutting the tree down we were able to peel back the bark and found the tree riddled with worms or larvae about an inch long and white. They had burrowed into the tree and had left holes in the tree.

We have 2 others about the same age and in close proximity to the one that died. The trees are at the West end of our house and face South.

As we have the other two trees, which so far look all right, we would like to save or protect them from this. Any information you could impart to us to help would be greatly appreciated. Thank you,

Baltimore County Maryland

1 Response

There could be several reasons for decline such as drought, poor drainage, vole damage, etc. When subject to this insect and disease can be a problem but they are secondary factors.

This tree sounds like it was already declining in the fall and died back this spring. In general borers attack stressed trees. There is no chemical control. Keep your other trees well watered during dry periods and make sure mulch is no thicker than several inches and away from the trunk. Once a tree has died it is difficult to diagnose why. Next time please send us photos of the symptoms once they are noticed so we can see what you may be dealing with.
mh