Perhaps you have seen this wasp flying over the landscape at about 12” above the ground circling in a mass of its fellow wasps. What is it doing? Well they are selecting mates and mating, prior to laying eggs on grubs in the landscape.
At first glance it may appear as if someone has whitewashed your landscape ornamentals. But upon closer examination with a hand lens you should notice the white hyphal growth that confirms the presence of the disease known as powdery mildew. Powdery mildew is a common disease that begins to appear in mid-to-late summer in Pennsylvania on a wide array of woody ornamentals.