Q: I was trimming the sucker growth off my live oak trees the other day and a lot of them, not all, but a large number look like something is shredding the bark on the stem, not eating it or taking it off, but shredding it like tiny cat scratching. What is causing it, is it bad for the tree and if so what can I do?
A: What you have is Cicada damage. The damage it self is not bad for the tree, most of it is always on the small twigs and can make the tree look bad but does little harm. Fortunately this most often is in the heat of summer and not in spring, other wise it could open the tree up to oak wilt or decline. But the insect that spread the disease are not active in extreme heat. The cicada roughs up the bark while laying its eggs that hatch into a small larvae that then drops to the ground and burrows in to feed on roots and other plant parts but will do little more to damage the tree. Spraying is not practical as the adults fly around from area to area and most trees are too large to treat effectively. If you must have something done, there are some tree drenches available retail that the average home owner can use or contact a certified arborist for more detailed information and options.