The Ohio State University

Home LandscapeNotes Folks at the Ohio Department of Agriculture finished their sampling of EAB trap trees and we are now up to 34 Ohio counties with confirmed infestations/detections. Remember that the Federal USDA has the entire State of Ohio under quarantine which means that you have to jump through their hoops in order to transport ash products across the state borders. Within Ohio, infested counties are under a state quarantine that prohibits movement of ash trees, ash tree products (e.g., lumber logs) and ALL hardwood firewood from being moved from infested counties into uninfested counties. You can move these products if you follow quarantine procedures (e.g., removing bark from logs to be cut for lumber, chipping to a certain size, etc.).

The current quarantine counties can be found on our OSU Extension web site on EAB:

http://ashalert.osu.edu

Check under the links where you'll find the state and federal quarantine maps as well as quarantine information. During the winter months, we have also added improved PowerPoint Presentations on EAB detection, identification and control.

Speaking of controls, now is a good time to review EAB controls. Not much has changed from last season except there are some new insecticides that have been evaluated and show improved promise of control. However, these haven't been registered yet but the companies are working on them! Basically, for homeowners who wish to try and control EAB, the easiest product to use is the Bayer Advanced Tree & Shrub Concentrate. Simply follow the label instructions for drenching the base of the trees. This application should be made by mid-May for season-long control. Professionals have several imidacloprid (Merit, etc.) products as well as Safari and a couple of injection materials.

Now, what trees should be treated? Obviously, this is a touchy question as everyone has different values concerning the ash trees in their landscapes. Many municipalities have run the long term numbers on the cost of treating trees. In general, the cost of control exceeds the cost of replacing the tree after five or six years, so many municipalities are adopting a multi-year removal and replacement strategy. However, there are some municipalities that have identified certain ash trees that they want to try and protect. Likewise, individual home owners certainly have the option to treat their own trees and keep them alive. However, remember, once treatments have started, you'll need to treat the trees every year!

When should you start treatments? Again, there is a lot of misunderstanding on this question. First, if you are in a county where EAB has not been detected, there is no reason to spend money on treatments.

If you are in a county where infested trees have been identified, look at the state detection maps (linked through our EAB web site). There are county maps that have pretty precise locations of EAB detections. If your ash tree is within a mile of where a known infestation is located, it's probably a good bet that you should begin treatments.

If you think that an ash tree is infested AND you want to try and save it, the reality is that this will be a tough task. Even if you are successful in eliminating the current infestation, you should ask yourself whether damage will be so severe that the tree has lost its aesthetic value. If this is a real risk, you should probably just replace the tree.

reprinted from P.E.S.T newsletter by David Shetlar (31 March 2008 Vol. 17, No. 2)

Posted by David Shetlar