Emerald Ash Borer Update

Emerald Ash Borer feeding galleries

Last year at this time, we were consumed with figuring out how to deal with the reality that Emerald Ash Borer had been detected in Bucks County. A year later, this pest seems to have faded away. Not so!

While no additional detections beyond the original site in Warrington have been noted, the bug has not disappeared. There were many ash trees infested at this site and no doubt the adults that emerged from those trees flew off to mate and infest other trees. Studies of previously infested sites indicate that the infestation will move about ½ to one mile per year, even when attempts to eradicate the insect are in force. In addition, the infestation in Warrington is estimated to be several years old. So…..I figure EAB is most likely already established a few miles from Warrington, it just hasn’t been detected yet.

Still, the good news is that folks who fall outside of a 10-15 mile radius of Warrington can wait and watch. Researchers say that treating trees beyond this is a waste of money. This “lull” period provides time for people and communities to make a plan for the day when EAB arrives. It’s a question of when, not if, and that’s an important fact. There is no doubt that ash in Buck County will be killed when this insect reaches them.

For a refresher on Emerald Ash Borer, see this site.

On Thursday May 9, The Pennsylvania Horticulture Society will conduct and Emerald Ash Borer workshop at Neshaminy Manor Center for municipal, private and community professionals who are planning for the impacts of EAB. Contact PHS to register. Pre-registration is required.

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.

Watch Your Ash

The other day I found myself taking a cross country walk through suburban Doylestown Township. From Cross Keys to Delaware Valley College, if you know the territory. I was trying to stay out of the sun so I stuck to the side streets, looking for shade. I found a lot of shade but as I proceeded though one particular development I noticed something disturbing. Almost every tree I walked under was ash. Green Ash is a great tree -tough as nails and well adapted to our region. Not much for flowers or fruit but it's a good choice for shade. Or it was.

As you may have heard, there's a new pest in Pennsylvania called Emerald Ash Borer. Just about one year ago the pest was found on the western Pennsylvania border. It traveled east from Ohio. The original infestation in the United States was found in Michigan in 2002 where it has devastated more than 30 million ash trees. Who knows how long it will take for this boring beetle to reach our end of the state but experts agree, it is just a matter of time. The larval stage of this insect destroys the water and nutrient conducting tissue just beneath the bark, causing trees to die. Symptoms include back cracking, woodpecker activity, crown die-back, and ultimately , tree death. Several other borers attach ash. Check symptoms to distinguish between them.

So, as I enjoyed the shade of these fine trees I could not help but think that some day they are likely to be wiped out by a new invasive pest. Forget about eradication. This cat is out of the bag. Individual ash trees will be candidates for insecticide treatment but wholesale protection of woodland trees and most landscape trees is just not feasible. Don't panic now and call the arborist. We'll have more specific instructions when it finally gets here. No sense in treating trees before the bug is here.

For now, enjoy the shade. Think twice before planting ash (we're talking the genus Fraxinus not mountain ash, Sorbus). Be glad that Pennsylvania has only a modest amount of ash in it's forests and landscapes. It may be many years before eastern Pennsylvania deals with this pest. Regulatory agencies are monitoring throughout Pennsylvania to track it's progress. If you happen to see a big purple box hanging in an ash tree, this is one of the monitoring stations.

Click on the Emerald Ash Borer link above to get the full story. You can follow the progress of this insect and read it's history from this site. And watch your ash.