Emerald Ash Borer in Minnesota

Findings in Minnesota

As you no-doubt are aware, there has been a confirmed finding of emerald ash borer (EAB) in Minnesota. The initial detection was in 3 different ash trees on Wednesday, May 13, 2009 in St. Paul (slightly East of 280 and slightly North of I-94). Additional findings have been made in the Fort Snelling area and in SE Minnesota. Unfortunately, this most likely is not the only infested areas within the metro as there were trees within these sites that appeared to have been infested for many years.

EAB is a non-native invasive insect from Asia that kills all native Minnesota ash trees. According to the Minnesota Department of Agriculture (MDA) no evidence to date of resistance against EAB has been found in any native North American ash populations. In areas where EAB has become established in North America, ash tree mortality rates approach 100%. Insecticide treatments are available that can in some situations protect individual trees from EAB attack. The damaging agent is the immature stage-the larvae-of the insect.

Contacting a Certified Arborist

The larvae kill ash trees as they feed on the living tissue under the bark. Usually the symptoms are very subtle. Contact a local consulting certified arborist for an inspection and treatment options. Timing is crucial to any treatments - trees that are already infested are less likely to survive. To contact an International Society of Arboriculture (ISA) certified arborist visit the ISA website.

The Minnesota Department of Agriculture (MDA) is the lead State agency handling EAB. They are in the process of defining the boundaries of the infestation in St. Paul. Once the extent of the infestation is determined, formal quarantine limits will be established. Because the insect is so difficult to detect, once EAB is detected in an ash tree, it has likely been in an area for three to five years.

On their own, EAB spread at a rate of ½ to two miles per year. However, the human spread of firewood and goods has accelerated the rate at which it is establishing in new areas. The mature beetles can fly two to six miles in its short three-week life span.

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.