A sharp mower blade is even more important when turf starts putting up seed heads. The seed head stems are much tougher than the grass blades and more likely to shred. With normal use, mower blades should be sharpened about every 10 hours of use. A number of tiny non-stinging wasps, mites and flies cause abnormal growths to develop on the leaves, twigs or branches of oak trees. These galls can include growths that are round, spiny, flattened, elongated or star-shaped.
Galls form in response to a chemical that the insect injects into the plant tissue.
Eggs laid by a mature female hatch into legless grubs around which the gall forms. The larvae feed, develop, and pupate inside these galls. The adults may emerge either the same season or may overwinter inside the gall depending on the life history of that specific insect. Generally, these gall insects do not cause significant damage to their hosts, though some of the leaf galls can cause enough deformity to make a tree unsightly. Also, severe infestations of twig galls can cause twig dieback or, rarely, tree death.