They are here. These tiny, iridescent, green invaders were discovered in Connecticut on Monday. The arrival of the Emerald Ash Borer (Agrilus planipennis) was confirmed on Wednesday USDA Animal and Plant Inspection Service (USDA APHIS-PPQ) offices in Michigan and DC, and the news was reported by the CT Department of Energy and Environmental Protection (DEEP) in a news conference on Friday.
Connecticut joins 15 other states where infestations of the Emerald Ash Borer (EAB) have been detected. Discovered near Detroit in the summer of 2002, EAB probably arrived in the United States on solid wood packing material carried in cargo ships or planes originating in its native Asia.The EAB is responsible for the death and decline of tens of millions of ash trees, of all species, from the Mid-West to New York State and south to Tennessee. It is a small, metallic green beetle, approximately 1/2 inch long to 1/8 inch wide. Adults emerge from the bark of infested trees leaving a small D-shaped exit hole roughly 1/8 inch in diameter. The adult beetles nibble on ash foliage but cause little damage. The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients.
In anticipation of the EAB's arrival from New York, over 500 purple detection traps, containing a chemical lure, were set up across the state. Traps, however, were not the means by which the EAB’s presence in Connecticut was first detected.
The EAB is a favorite prey of Cerceris fumipennis, a ground-nesting, non-stinging native wasp, which hunts beetles in the family Buprestidae, including the EAB. Scientists from the Connnecticut Agricultural Experiment Station (CAES) in New Haven have been using Cerceris as a bio-surveillance tool. They recruited an army of citizen scientists as “wasp watchers,” monitoring dusty playing fields adjacent to woodlands for hours on end during the peak of Cerceris hunting time — late morning to early afternoon on hot, sunny July days! Their assignment? To intercept the Cerceris prey before she (always a female) can get her catch into her underground burrow. If the EAB is in the area, it is evident in the Cerceris catch.
It was a wasp watcher who made the initial discovery at Canfield Park in Prospect, in northern New Haven County. She caught the Cerceris wasp carrying the female EAB that was sent to APHIS for confirmation. Since Monday, watchers have captured 25 more EABs at Canfield and three more at nearby Fusco Field. Additionally, nine more EAB were discovered in a catch sample submitted by another Canfield Park watcher. This triggered a check of purple traps in the area. While the one near Canfield was empty, another trap in Prospect yielded three, and three more were found in a trap in Naugatuck. Summer surveillance in Fairfield, Litchfield, and Middlesex counties has not yielded any EAB; the newly confirmed infestation seems to be confined to the Prospect area.
The discovery in Prospect is, however, one of grave concern. DEEP Commissioner Dan Esty stated in a press release, “This is a disturbing discovery and one that has the potential for great environmental harm in the state. Connecticut has more than 22 million ash trees. The presence of EAB here could have a devastating effect on the beauty of our forests, state and local parks and neighborhoods, as well as the state’s wood product industries.” Ash makes up 4% to 15% of Connecticut’s forest and is a common urban tree.
How did EAB get to Prospect? Prospect is a good distance from Dutchess County, New York along the Hudson, where EAB was detected earlier this year.
Have you noticed the Do Not Move Firewood billboards along the highway? The EAB has great flight potential. Movement of firewood containing EAB to a new location gives the beetle the opportunity for rapid expansion of its territory — the quickest way to spread the infestation. DON’T DO IT!
Scientists fear the Naugatuck State Forest in the immediate area is also a likely site for the presence of EAB. Right now the focus is on trying to establish the borders of the current infestation. More purple traps are being deployed. DEEP is establishing a quarantine zone that would prohibit the movement of certain wood products out of New Haven County, suspend all timber contracts and firewood permits for state forest lands in New Haven County, and maintain a ban that has been in place against bringing any firewood into state parks and forests.
Thanks to Cerceris and the wasp watchers, we know EAB is here. Have we learned about the presence of EAB in time to save our trees? That is the question.
What can you do? Be alert. In CT, notify CAES (203-974-8474) or email CAES.StateEntomologist@ct.gov if you see the D-shaped hole on an ash tree. For anywhere else, call 1-866-322-4512 or go to www.emeraldashborer.info. And don’t move firewood!
NOTE: I am following this story closely. I was trained as a wasp watcher. I have a 27- year-old white ash in front of my home; I saw it get planted and I have watched it grow up. Check back for more details. I’ll post updates whenever I receive more information.