For whatever reason gall insects are rearing their ugly heads and causing odd growth on leaves of trees in the landscape. Oak Vein
Pocket Gall is my number one plant problem so far this year.
This damage is caused by the maggots of certain midge flies. These very small insects lay eggs as leaves begin to expand and flatten in the spring. The maggots that hatch from these eggs move to the veins and start feeding. Gall tissue then forms and provides a protective covering for the maggots. By mid-spring, development is complete and the now mature larva drop to the ground and pupate.
So what should you do about it? Vein Pocket Gall midges are difficult to control and do not cause significant damage to the host tree and therefore control is not warranted
photo credit – Franco Folini