Emerald Ash Borer
Common Questions on the Emerald Ash Borer
Dr. John Ball, extension forestry specialist, South Dakota State University, forest health specialist, SD Division of Resource Conservation and Forestry; phone 605.688.4737. email firstname.lastname@example.org
Emerald Ash Borer
Again, it is important to point out that the emerald ash borer has not yet been detected in South Dakota (April 2017). However ash trees exhibiting the following symptoms may be infested. Look for ash trees that have some dieback or are standing dead. Oftentimes these trees will have the bark shredding off due to the tremendous number of woodpeckers feeding on the larvae beneath the bark of the infested tree. If the bark is pulled off the tree you should be able to find S-shaped tunnels on the surface of the wood. These narrow tunnels, about 1/8-inch wide, will be packed.
It is important to remember that there are also many native borers that attack ash trees, the most common being the native ash borer. This insect can be separated from the emerald ash borer by its larger tunnels that are clear of sawdust. The exit hole made by these insects is round and almost the diameter of a pencil. There will often be sawdust around the base of trees infested by the native ash borer.
Since the emerald ash borer has not yet been found in the state there is no need to begin removing ash trees. However, it is probably a good idea to stop planting ash. Ash trees make up almost 1/3 of all the trees planted in our communities and also are one of our most common windbreak species. There are many other trees that can be used as ornamental or windbreak trees and we should start planting trees now so when the emerald ash borer arrives we will not loss the majority of our community forests and windbreaks in a short time period. We also do not want to repeat the mistake made with Dutch elm disease where the diseased elms were replaced with a single species - ash. The best recommendation for homeowners is to look at what their neighbor’s are planting and plant something else! We want to develop a diverse forest, one that is not all susceptible to a single pest.
It is also too early to begin pesticide treatments. While there are effective treatments for the emerald ash borer they should be consider means of prolonging the tree rather than saving the tree. Experience in other states has shown that the beetle population can continue to increase in a treated tree if there is a high population of beetles in the area and these trees may die despite the use of insecticides. When the beetle is found in a region of the state, homeowners may want to consider treatments but the most effective are the ones available to commercial applicators and it may be best to leave the management on the problem in the hands of professional tree care companies.