Meant to ask this back in July, which was peak season, but has anyone seen little circular piles of sand with pencil-sized openings in the center anywhere in Newton? They would most likely be found in hard-packed sandy soil, in sun, but within a couple hundred yards of a woody area, often, but not exclusively, on basepaths or around ballfields. One colony I’ve been monitoring is along a grassy residential berm in Needham that seems to have a lot of sand underground.
They are made by Cerceris fumipennis wasps, which are being used as a bio-surveillance tool to detect the Emerald Ash Borer before it might otherwise be detected. (They do not sting or bother people!) The EAB kills ash trees like the more publicized Asian Longhorned Beetle kills lots of species, by tunneling under the bark and destroying the tree’s circulatory system. It has been spreading outward from Detroit since 2002 (probably arriving in the US in packing crates). This summer it was detected east of the Hudson River in N.Y. for the first time, and in July was found in Prospect and Naugatuck, CT (much further east from the N.Y. border than expected), by monitoring Cerceris wasp nests. The wasps hunt Buprestid beetles (of which EAB is one type), and bring them back to their nests for their larvae to feed on. Monitoring involves picking up “discard” beetles, and catching wasps until they drop their prey, and collecting the prey.
I would really like find a colony in Newton to monitor next summer, and the Mass. Department of Agricultural Resources and the USDA are looking for more colonies generally. They think the EAB is probably already in Massachusetts, but not yet detected.
In Newton, ash trees only make up maybe 1-3 percent of street trees, so this particular bug would not be as devastating as it has been across the Midwest where many towns are 25 percent ash trees, because that’s what they planted when Dutch elm disease killed the elms. But they are very nice shade trees, and with our preponderance of Norway maples, anything that’s not is to be especially valued. Unlike with ALB, where infested trees are destroyed to prevent spread, healthy or lightly infested ash trees can be saved with injections that kill the EAB, which anyone with a nice ash tree would probably want to do, so it’s worth finding it early.