Meet the Beetles
They’re non-native insects imported from Asia. They are detrimental to the structure of Ash Trees, and they’ve become widespread across the United States. They’re the Emerald Ash Borers (EAB), and they need to be stopped.
Eric Foley of Maier Tree & Lawn states that EAB were first found in Minnesota in 2013 and have since destroyed an alarming number of our trees. They have been recently spotted in counties of Southeastern Minnesota. The first U.S. sighting was in Detroit back in 2002. Since then, they have managed to spread east all the way out to Pennsylvania and as far west as Colorado. Because Minnesota is home to over 1 billion Ash Trees—more than any other state, our trees are at a very high risk for infestation.
The adult beetles are quite harmless to the tree; in fact, they just feed on the leaves of the tree. The problem lies within the larvae. Upon hatching, they begin tunneling into the bark, which subsequently cuts off the tree’s water and nutrients. Adults feed the most during the summer, while larvae are most active in the fall and winter.
Ash Trees alone make up a significant portion—about 35 percent—of all the trees in urban communities. “In order to successfully replace what is lost to EAB, trees of several different species must be planted in the given area,” Foley said. “By using this proactive approach, further tree loss can be more effectively prevented,” he added.
Foley says that once a tree becomes infested, it’s not necessarily doomed. If it is recognized early enough, the tree can be preserved. However, there is quite a lengthy, ongoing process involved with preventative and treatment measures. An arborist must first take an inventory of the existing Ash Trees before assessing their location and condition. Next, they determine which trees are worth preserving based on the tree’s structure and location, keeping in mind that not all trees are worth saving. Trees that are suitable for preservation will receive an injection into the trunk, which gets spread throughout the tree via the vascular system. The dosage is based on the size of the tree, and it kills insects that attempt to feed on the tree for the following 2 years.
When the USDA confirms infestations in a given county, treatment begins right away. If you think your trees may be infested by EAB, you are encouraged to contact a local arborist, who can then investigate the trees on your property. Signs of EAB include D-shaped holes in the trunk, as well as a large increase in woodpecker activity. If the infestation is near ground-level, it is likely too late for treatment. Even so, seeking direction from an arborist in such cases could help prevent further infestation in other trees. “It is important to remember that it is an infestation, not an infection, so treating just one will not prevent others from becoming affected,” Foley says.
Hundreds of thousands of Ash Trees have already been wiped out by EAB; don’t let yours be next.