Emerald Ash Borer

Emerald ash borer (EAB) is an aggressive and invasive beetle that infects and kills ash trees. EAB attacks all species of North American Ash. EAB eggs are laid on the bark or in small cracks. Once larvae emerge from their egg, they tunnel into the cambial layer of the tree (the layer beneath the bark). The larvae are 1” to 1 1/4” when fully grown with a flat body and brownish head. At this point in development, the beetle has no legs. The larvae wind back and forth as they feed under the bark and create distinct, S-shaped tunnels in the wood and cutting off nutrient flow throughout the tree. Larvae feed under the bark until late fall and then winter in the tunnels they created. The fully-grown larvae live through the winter in these tunnels, transforming into pupae the following spring and from there into an adult. The adult beetle is a small green beetle that is not often seen. The adult beetle is 1/3” to 1/2” long with a slender body. They are bright green in color and may have a copper color just behind its head.

Symptoms of EAB infestation

White Bear Township has found EAB throughout the Town. On average, trees are killed within four years of being invested, though complete devastation can happen between two and five years. When first infected, symptoms are hard to notice, but often begin with blonding. Blonding is seen as light patches of bark often starting at the top of the tree. During the second year you may start to notice increased woodpecker activity and foliage thinning. By year three, canopy thinning is pronounced as is greater woodpecker activity. By the fourth year, canopy dieback has greatly increased and you may see vertical bark splits in the main trunk.

What to do if you are concerned you have EAB?

First is to confirm that your tree is an Ash tree. Once confirmed, you can choose to treat or remove the tree. Treatment of a tree can be done proactively or during early infestation. Lightly infested trees that show little signs of decline can recover if treated. Infested trees with more than 50% of canopy dieback are not favorable for treatment. While treatment may be an option, it should be noted that treatment cannot reverse damaged that has been already caused by the EAB. The decision to treat, remove, or retain a private tree rests with the property owner. Homeowners can use any tree contractor that is licensed in the Township.

Arrest the Pest Hotline

Residents should learn about this threat to our ash trees and be on the lookout for infested trees. If you suspect a possible EAB infestation, call the MDA "Arrest the Pest Hotline" at 651-201-6684 Metro Area, or 888-545-6684 Greater Minnesota or Email Arrest the Pest.