Wednesday, March 14, 2012

Yes, Kiss Your Ash Goodbye

Emerald Ash Borer larval feeding injury
About nine months ago, this blog described purple traps hung throughout the Delaware Valley which are designed to detect an important pest … Emerald Ash Borer (EAB). The traps were not successful in detecting this insect but a sharp-eyed arborist was. Last Friday I got a call to look at some ash trees that were ravaged by woodpecker feeding. Beneath the bark, signs of larval tunneling were obvious. A few days later, Pennsylvania Department of Agriculture entomologists visited the site and verified that this was indeed Emerald Ash Borer.

Bad news for ash trees.

You can read the blog of June 11 last year and get the story … nothing has changed except that a detection has been made about 100 miles east (Warrington, PA, Bucks County) of the leading edge of the Pennsylvania EAB infestation. About the only good news is that a tremendous amount has been learned about this insect in the last 10 years. See this Penn State site or this National EAB site for solid, research-based information. The PSU “Frequently asked questions” feature is a good starting place.

For tree owners, the time has come to consider the fate of your ash. Depending on who’s counting, this insect has killed between 40 and 50 million trees between Michigan and….. Warrington. It is in 15 states and two Canadian provinces. It’s a tree killer. Infested ash die.

Individual trees can be protected with insecticides. Some can be applied by homeowners but, from what I read, the best product is available to arborists only and has to be injected. Upside? Two years of control.

Another hopeful thought is that entomologists now have several parasitoids, (bug killing bugs) that may provide some control of EAB… and perhaps the site recently detected would be a release site for them. That would be nice. Cross your fingers.

But don’t expect predators to catch up to EAB in Bucks County before a lot of damage is done. For now, learn to recognize ash . Think about whether it is really important to preserve those that you see. It is not practical to treat every ash tree. Remember, treatment provides only temporary protection, not immunity or a cure.

Those considering do-it-yourself treatment will find instructions here

Anyone following the story of Emerald Ash Borer knew that it was only a matter of time before this insect would be found killing ash trees in eastern Pennsylvania. Maybe this knowledge lessened the blow a bit. Also, those who closely observe tree and pest interactions know that this is one of many associations between an insect (or disease pathogen) that results in catastrophic impact on a species. See Dutch Elm Disease, Chestnut Blight or Hemlock Wooly Adelgid. More recently, Thousand Cankers Disease of Black Walnut.

I never paid much attention to ash trees until EAB arrived in Pennsylvania five years ago. Now I see them everywhere. Not for long.