Wasp Attacks on Black Oaks May Be Spreading on Island

Inside the Polly Hill Arboretum office on Monday afternoon sits Collections and Grounds Manager Tom Clarke with a number of black oak twigs and branches on his desk, one just brought in by arborist John McCarter an hour earlier. With acorns dangling and new foliage sprouting, the twigs are seemingly healthy.

Look closer and each twig has hundreds of miniscule holes; the once smooth, skinny branches are now bumpy and swollen.

Once emerging from these tiny holes were the cynipid gall wasps currently attacking black oak trees up and down the Island.

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