Emerald Ash Borer (EAB) Fact Sheet
What is emerald ash borer?
The emerald ash borer is a green beetle that can devastate ash tree populations. The adult beetles chew on ash leaves but do not cause much damage. However, they lay eggs in the bark of ash trees. When the eggs hatch, the larvae feed on the layer of tissue below the bark. This disrupts the trees' ability to transport water and nutrients. Eventually this will kill the ash tree.
Emerald ash borer in Minnesota
The emerald ash borer was first discovered in North America in 2002. It is believed that the beetle arrived in shipping crates from Asia. Since then, it has been identified in multiple states across the east and midwest. In Minnesota, EAB was discovered in St. Paul in 2009 and Minneapolis in 2010.
Since its discovery, EAB infestations have killed hundreds of millions of ash trees in North America. Minnesota has one of the largest populations of ash trees in the United States, which makes it particularly susceptible to EAB infestations and damage.
What are the signs or symptoms of EAB infestations?
- Loss of green color in the uppermost leaves
- Thinning and dieback of the crown
- Sprouts growing from the roots, trunk or branches of the ash tree
- Woodpecker holes
- Splits or D-shaped holes in the bark
- S-shaped zig zags
Unfortunately, most of the time EAB infestations only become apparent once a tree has been heavily infested. Ash trees do not have a way to defend themselves against this invasive species, so unless they are protected with insecticides, the EAB infestation will kill them.
The recommended treatment is the root injection method, which injects the product directly into the tree. A professional tree care company that is a licensed pesticide applicator will need to be hired to do this kind of application. This treatment can be done from June through September.