These pin oaks are shedding leaves, and large parts of some of them have leaves that look white from the ground. The culprit is scarlet oak sawfly larvae. I have never seen damage quite like this from this insect. It’s unusual for it to reach such a high population that it defoliates the tree like this, and there ARE natural predators that usually keep it in check. But in this case it could impact the tree’s health, so control would be justified. Control, by whatever method, would need to be done soon. Otherwise the larvae will pupate, and later in the year the adult wasps will emerge and lay eggs and there will be another generation!
This weeping willow in Harleysville has adult imported willow leaf beetles feeding on its leaves. They won’t cause much damage. But the population of beetles is rather high, and they will soon lay eggs. When the larvae of the next generation emerge from the eggs, they will feed on the leaves in a skeletonizing pattern, and there will be enough of them to defoliate the tree. The client is aware, and he will probably spray them.
The way this client found me is a little bit strange. He found my website by googling “bacterial leaf scorch” (I have articles posted about my experiences with BLS). That’s what another “arborist” told him was wrong with his ash tree. And that the disease would kill the tree, so he should remove it. Well, ash trees have a few problems around here of late, but bacterial leaf scorch isn’t one of them. Anyway, the tree didn’t look good and we talked about the true ash ailments – ash anthracnose (which the tree did have) and emerald ash borer (which hasn’t been found close to here yet). In the end, he agreed we should inspect the tree for EAB, just to be sure. Today, Ricky and Dave climbed
