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Longtime readers may recall that back in 2012 and 2013 I was looking for colonies of friendly wasps that would find the Emerald Ash Borer (EAB) when it turned up in this area. I did find some colonies, and in 2016, the best colony (best because they drop a lot of dead beetles), at the Hunnewell Playground Dog Park in Newton Corner, started finding EAB. That same summer, Director of Urban Forestry Marc Welch found the first known tree killed by EAB in Newton, on the Washington Park island in Newtonville. Since this Fall 2016 article in the Newton Conservators newsletter, there have been a couple more locations: four large dead or dying ash trees on conservation land across from Mason-Rice, and a couple by the Newton Country Day School on Centre Street.

Thinning in upper canopy. If your ash tree looks like these, call an arborist ASAP.

But this summer is feeling like the breakout year for this invasive beetle, especially in Newtonville. In the last couple of weeks I’ve come across a heavily infested ash on California Street (first I’ve seen north of the Mass Pike), and a similar one already tagged for removal on Ward Street (the one in the video above). Marc reports seeing infested ash on Tree Ordinance site reviews (when developers plan to cut trees). And today I found myself knocking on a couple of doors in Newtonville center after noticing private ash trees with dying upper branches and finding one or two D-shaped holes on the trunks. In one case, the owners had treated their tree last year with something that works on EAB, without knowing specifically that it had EAB, and say it looks a lot better this year than last.

California St at Nevada

So if you have an ash tree that you value and want to keep around, please check out emeraldashborer.info which is a great resource, and consult an arborist from a good tree care company about treatment options. The most used treatment protocol involves trunk injections every other year. Not all ash trees will be worth saving, but for a large, healthy tree, the cost of treatment, even over many years, will likely be less than the cost of removal, and you will have the enjoyment of the tree. Treatment is most effective if started before a tree is infested, or at least before extensive canopy death, and is recommended within 15 miles of a known infestation, which would include all of Newton.

Long term, there is some hope for a biological control, according to UMass Extension’s fact sheet. Four different parasitoid wasps have been approved for release in the U.S., and a very small percentage of ash in North America show signs of resistance to EAB. So perhaps genus Fraxinus will not become as rare as the American chestnut.