Thursday, August 5, 2010

Daily Calls

Horned oak gall is keeping my phone busy this year. This unsightly gall occurs on pin oak, shingle oak, and cherrybark oak, and it seems to be worse every year. Horned oak gall is caused by a wasp which lays its eggs in oak twigs, and the gall develops around the larvae as they grow.

One adult will eventually emerge from each of the horns. When this malady girdles enough of the twigs on an oak, the tree falls into a decline, and dies. There is not any treatment available to intercept the egg laying wasps, and if your tree smells right to the little buggers, it's a goner. One new thing I am seeing this year is that gray squirrels are clipping off infected twigs; letting them fall to the ground. The squirrels then go to the ground and chew up the galls in order to eat the wasp larvae. This behavior may be our best hope to save valuable shade trees.

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