An Emerald Ash Borer Experiment at CVS Park.

Warren wanted to show me the results of a recent treatment his company had given to a tree, so he pulled the truck over at the Village Center Park (a.k.a. CVS park) in Lower Frederick Township. Township park board members had been working to transform the lot into a “village square” center. The design plan included gardens and other natural features that benefit pollinators, absorb rain, improve biodiversity, and reduce maintenance needs. Sadly, as many as 35 ash trees on the property were dead or dying as result of the arrival of the tree-killing emerald ash borer (EAB). The immediate area was dotted with the skeletons of standing dead ash and the gloomy prospects of soon-to-be-dead ash.

One still-living, shade-producing ash tree in the park showed signs that it could still be saved by injection of a systemic insecticide into the trunk, systemic meaning the tree will carry the material through its vascular system.

After he and integrated pest management specialist, Noelle Halter, agreed it would be worth the effort, the idea was proposed to the township manager. Then, during the week of June 15, 2020, Noelle, who was also serving on the township's board of supervisors, donated her time, Jacobs Tree Surgery (JTS) donated the material, and the tree was treated. By that time, JTS had been performing such injections in the township for 4 years, beginning when an infestation of EAB was confirmed within a 15-mile range. Doing so prior to that would have been wasteful and unnecessarily injurious to the trees. But this particular ash tree had never been treated. Easily accessed, Warren took the opportunity to test the results. He was curious as to how quickly the tree would transport the insecticide through its system. The primary target of the treatment is the EAB larvae, which lives unseen below the bark where it consumes the tree’s cambium (which carries water and minerals up) and phloem (which carries photosynthesized food down). However, being early summer, adult EABs had emerged and were seen hanging around outside, chewing on the leaves.

Thus, a white tarp was staked to the ground under the canopy following injection.

The idea was to test the efficacy of the insecticide and determine when it had reached the leaves by collecting the results: the dead adult beetles. The tarp was in place to catch a sampling of the tiny EAB after they fell and before they disappeared into the grass. It took less than one week of typical sunny, summertime weather for Warren and Noelle to get the answer. Victims began falling within a week.

Now, the ash tree continues to stand in the Village Center, offering many ecosystem and aesthetic services. A variety of new trees, shrubs, and other vegetation will be planted to replace those that have died or are doomed. Our visit to the park was brief. We climbed back into the truck to get back on our way, because there was much to do in the battle against a seemingly endless parade of threats to our urban forest.