A: This pest is crape myrtle bark scale which sucks sap from the plant, making it less vigorous and reducing bloom. Sticky residue from the insect coats branches, stems, and leaves, then airborne molds grow in the sugary material and blackens the trunks of the plant. It’s not likely to ever kill the plant outright, but it’s definitely undesirable.
The insect will get into every nook, cranny, and crevice in the branch structure and thus it’s hard to spray for. The good news is that it is very easy to treat with a drench insecticide. We recommend our Bonide or Ferti-lome Systemic Insect Drench. Mix in water according to label instructions and pour the drench slowly around the base of the crape myrtle trunk. The pesticide will have to travel up the trunks and branches, so give the product some time to work – typically, 2-3 weeks, and the scales will be dying. This treatment will fix the problem for months. Check the plant closely for re-treatment if necessary next April.
Fertilize the plant vigorously this September, and your plant will be set on the road to a good recovery.