Tree Pest Alert: Twig Girdler Beetles
September 28, 2015
Have you noticed small tips of branches on your red oak trees suddenly turning brown and dropping off the tree? Twig girdler beetles may be attacking your tree. The damage these pests cause can be quite alarming. While small populations typically aren’t cause for great concern, if left untreated twig girdlers can multiply into a full blown infestation and cause a lot of unsightly damage.
What is a twig girdler beetle?
The twig girdler beetle is a gray to brown colored longhorned beetle with a gray stripe across the wing covers. The adult female beetle will lay her eggs in the tips of the branches of your oak trees, directly into the branch tissue. As the female beetle moves back towards the tree trunk laying eggs, she cuts rings around the twigs, causing them to die and fall off.
In the fall, the new larva emerge and then overwinter. Once spring weather returns they grow rapidly and start feeding on the soft severed ends of the branches. They then burrow back into small holes in the branch and re-emerge in summer as adults. This cycle happens once per year.
girdlers can also be a problem on pecan and hickory trees; right now
we’re seeing them crop up predominantly in red oak trees.
What to look for
During late summer, look for small branch tips browning. In late-summer and fall, you may see many small severed twigs on the ground under your tree, or hanging loosely within the canopy. These are signs you probably have twig girdlers in your tree.
What damage is done?
Small populations of twig girdler beetles might not do very much damage, but you will have some branch tips turn brown, die and fall off the tree. A large infestation can cause a tree to become weakened as the branches are continually damaged. Pests like these are often treated with systemic products that are consumed when the insect feeds on the tree. Twig girdlers, however, can be very difficult to control because adult females don’t feed directly on the tree tissue.
The best approach is to have your tree inspected as soon as you see twig girdler damage appearing. Your certified arborist can recommend a plan for reducing the twig girdler population and further tree damage.
Reduce continued infestations
Over time, if not treated, a few twig girdlers could turn into an infestation. Keep this pest at bay by always raking up fallen twigs and disposing of them; especially in late-summer and fall when the females are laying eggs.
When we perform work on your trees, we never leave tree debris on the easement. This debris, if infected with pests or disease, could potentially infect your trees again, or spread to surrounding trees.
Posted: September 28, 2015