My over wintered Butch T had a mild aphid infestation, so I got out the pyrethrin spray when I noticed what looked like specks of dirt on some of the leaves. Under a magnifying glass, the whitish specks looked more like the skeletal remains of some insect. They looked almost transparent, and did not move. These pics are the best I could do with my cell phone camera. The "skeletons" can be seen around the edge and top of the leaf.