Marin County 

In a way, Emerald Ash Borer (Agrilus planipennis) is the "sister" invasive species to Phytophthora ramorum. It's a problem in the midwest rather than the far west. Its epidemic developed over roughly the same time span as P. ramorum. Its mortality impacts are focused on one tree genus (Fraxinus, ash trees), in much the same way P. ramorum kills trees in two closely related genera (Quercus, true oaks, and Lithocarpus, tanoak).

One difference is that P. ramorum mortality is episodic, depending on climate, whereas the spread of EAB is less dependent on climatic cycles. Indeed, just last month the state of New York announced that the beetle has now been detected there, near Randolph in Cattaraugus County. Along with its recent move over to the Wisonsin/Iowa border, and recent finds in Kentucky and Minnesota, it's looking like EAB is on the march!

More EAB news is developing: researchers are investigating the possibility of using a biological control for the beetle, a parasitic wasp that lays its eggs in EAB eggs and larvae and kills them. Like any efforts to investigate and develop control of a pest, success, if it comes, will probably be many years down the road. Read one part of the story here.

And for more information about EAB in general, visit www.emeraldashborer.info.



Emerald ash borer feeding galleries, which have destroyed the entire cambium. Photo courtesy Daniel Herms, The Ohio State University, bugwood.org