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Emerald Ash Borer FAQ

How big a problem is Emerald Ash Borer?
Emerald Ash Borer (EAB) is now considered one of the most destructive forest pests ever seen in North America. The scope of this problem will reach the billions of dollars nationwide if not dealt with appropriately. State and federal agencies have made this problem a priority. Homeowners can also help by carefully monitoring their ash trees for signs and symptoms of EAB throughout the year. 

What are Oklahoma’s professional forest/tree managers doing to prepare for EAB?
Oklahoma forest and tree resource professionals collaborated on preparing a State Action Plan regarding an EAB infestation. The committee, Oklahoma Pest Action Council (OPAC), is composed of specialists from Oklahoma State University, University of Oklahoma, USDA Animal and Plant Health Inspection Service (APHIS), and Oklahoma Department of Agriculture, Food and Forestry.  Click here for a copy of this plan.

Has EAB been found in Oklahoma?
EAB was confirmed in Oklahoma in Delaware County October 12, 2016 in a trap monitored by APHIS.

Where did the EAB come from?
The natural range of EAB is eastern Russia, northern China, Japan, and Korea. Before June of 2002, it had never been found in North America.

How did it get into the United States?
We don't know for sure, but it most likely came in ash wood used for stabilizing cargo in ships or for packing or crating heavy consumer products.

What types of trees does EAB attack?
All species of North American ash appear to be susceptible. Trees in woodlots as well as landscaped areas are affected. Larval galleries have been found in trees or branches measuring as little as 1 inch in diameter.

How do I know if I have an ash tree on my property? 

Ash trees can be found in numerous counties in Oklahoma.  Varieties of ash were widely planted in our cities and towns across the state.  For information on how to identify an ash by 



What happens to infested ash trees?
The canopy of infested trees begins to thin above infested portions of the trunk and major branches because the borer destroys the water- and nutrient- conducting tissues under the bark. Heavily infested trees exhibit canopy die-back usually starting at the top of the tree. One-third to one-half of the branches may die in one year. Most of the canopy will be dead within two years of symptoms first appearing. Sometimes ash trees push out sprouts from the trunk after the upper portions of the tree dies. Although difficult to see, adult beetles leave a 1/8 inch diameter, "D"-shaped exit hole in the bark, when they emerge in May or June.

What does EAB look like?
The adult beetle is dark metallic green, and measures 1/2 inch long and 1/8 inch wide. 

How is this EAB spread, once established? 
Adults average distance to fly is 1-6 miles but have been known to fly as far as 10 miles from the tree where they emerge. Many infestations, however, were started when people moved infested ash nursery trees, logs, or firewood into uninfected areas. Shipments of ash nursery trees and ash logs with bark are now regulated, and transporting firewood outside of quarantined areas is illegal, but transport of infested firewood remains a problem.


Does it only attack dying or stressed trees?
Healthy ash trees are also susceptible, although beetles may prefer to lay eggs or feed on stressed trees. When EAB populations are high, small trees may die within 1-2 years of becoming infested and large trees can be killed in 3-4 years.

Can I save my ash tree from being infested by EAB?

The good news is yes, you can save your ash tree from the EAB infestation. There are professional and over-the-counter insecticides available to protect ash trees from EAB. However, insecticide treatments could be costly, and other options should be considered prior to treating your tree. Contact a tree care professional to consult about applying insecticide to your tree.  For more information on options