Protect your ash trees from pests

Published 10:03 am Wednesday, October 24, 2012

by Neil Clark
Southampton County 
Extension Agent

In the seemingly never-ending invasion of exotic invasive pests, 2012 brings us the Emerald Ash Borer.

And while this critter may not be the economic and aesthetic destroyer that it was in the Midwest 10 years ago, it may still be significant for some tree owners in Virginia.

After the initial Virginia detection of EAB in Fairfax in 2003, it was hoped that eradication efforts were successful. However, further areas have been detected since 2008, and in 2012 this exotic flat-headed borer has sprung up in nearly every corner of the state.

This summer EAB has been confirmed in the counties of Buchanan, Caroline, Giles, Hanover, Lee, Prince Edward, Stafford and Warren, adding to the already quarantined areas of Arlington, Charlotte, Clarke, Fairfax, Fauquier, Frederick, Halifax, Loudoun, Lunenburg, Mecklenburg, Pittsylvania and Prince William counties and the cities of Alexandria, Danville, Fairfax, Falls Church, Manassas, Manassas Park and Winchester.

As a result, the entire state has been defined as the quarantine area, which now allows green (non-heat treated) ash lumber and ash wood products, as well as hardwood firewood to move freely within the state. For additional information about the Emerald Ash Borer Quarantine call the Virginia Department of Agriculture and Consumer Services at 804-786-3515.

So what does this mean for southeast Virginia. Well, the U.S. Department of Agriculture’s Forest Service’s Forest Inventory and Analysis data reveal that the volume of ash in our non-urban forested landscape is rather small. The entire state is estimated to have 187 million ash trees, with most of them being predominantly in the western portion of the state and the Piedmont.

However, ash is a very valuable timber species used for furniture, flooring and most notably baseball bats. Forest landowners with significant ash volumes may want to step up their vigilance in monitoring their trees with the reality of a forced harvest under less than prime conditions.

More significant for the general population and general public around the southeast Virginia area are the number of ash trees in yards and urban areas that will be affected. Some may choose to fight for their favorite tree, and there is a solution for possibly saving an individual tree.

The EAB larvae live and eat the living, conductive tissue just under bark ultimately severing the lifeline between the sugar producing leaves and the vital roots. This provides both a challenge and an opportunity.

The challenge being that external sprays and natural predators have little to no effect. The good news is that systemic — meaning contained inside the plant — insecticides work well, and these are easier to apply, have a longer active life and are very precisely targeted to only bad bugs feeding on the plant.

Imidacloprid is the main insecticide labeled for EAB control. This can be poured around the tree and is then taken up by the roots where it is then effective within the cambium tissue where the borer larvae feed for the greater portion of the year.

This is effective, however, it must be done every spring. So continuing maintenance costs are a factor.

EAB is the “poster-bug” for the “Do Not Move Firewood” ad campaign. This common sense approach is quite applicable to avoid the spread of insect eggs that reside under the bark of trees. However, most people don’t think about that because they are out of sight, out of mind.

Instead most people see many dead solid hardwood trees, which equals a fantastic source of fuel wood. But when these bug eggs are on a truck and hauled 100 miles, the range of this pest is rapidly expanded.

Then when that firewood consumer loads a few pieces in their sport utility vehicle to use for a scouting campout that’s 100 miles away, the spread continues.

This practice too can be taken too far as most species of wood are moved harmlessly, but sometimes it’s best to get in the habit as firewood species can be hard to identify by the general public.

Unfortunately, like gypsy moth, stink bugs, bed bugs, etc., it seems the EAB is here to stay, and it will impact the face of our forests in a significant way.

NEIL CLARK is the southeast regional forestry extension agent and the unit coordinator at the Southampton Extension office. He can be reached at