Tulip poplar aphids are becoming active. These populations tend to grow for a couple

Tulip poplar aphids and lady beetle eggs. Photo S.D. Frank

weeks then crash as natural enemy abundance increases.  They are heavily parasitized and consumed by lady beetles. Note orange lady beetle eggs in the picture.  Thus treatment is typically not necessary though in some cases natural enemy populations may be insufficient due to urbanization or other stresses. Aphid management is described here:  http://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/note38/note38.html