Emerald Ash Borer
The Emerald Ash Borer (EAB) has killed millions of ash trees since its discovery in southeastern Michigan in 2002. Native to Asia, this insect was probably introduced to the United States in wood packing material carried in on cargo ships or airplanes. Through a combination of natural spread and human activity it is now found in the northern portion of the Midwest and east coast. Minnesota to Maine to Georgia. Colorado and Kansas also contain EAB. All of these locations place millions of additional ash trees at risk. It is spreading into New Jersey.
At Risk are: All native ash trees, including green, white, black, blue, and pumpkin ash.
The best protection from EAB is prevention. Treat all species of ash within a 15 mile radius of nearest known infestation. Infested ash trees displaying <50% dieback can be saved. However, treatments applied to ash trees in early stages of dieback will provide a higher likelihood for success.
Symptoms of an early infestation may be difficult to diagnose. Be on the lookout for multiple declining ash in a given area and D-shaped exit holes that are approximately 1/8 “ in diameter. As an infestation progresses, small vertical splits in the bark can be seen on twigs or the main trunk and woodpecker holes may be present on trees. Trees may die after 2-4 years or less.
- Preventive treatments will provide greater likelihood for success than treatments on infested trees.
- Recognize that it is difficult to detect the presence of EAB during the early stages of infestation, thus ash trees may be protected from EAB by applying treatments prior to the onset of visible symptoms.
- When symptoms are present, the tree has been infested for several years and the chance of saving it decreases. Trees with up to 50% symptoms have been saved. However, treating infested trees carries a higher risk of failure.
- Continuous treatments are required for continued protection. If applications cease, trees will become susceptible to the pest.