tortoise scale (Toumeyella parvicrnis) attacks mainly Scots
and jack pine. It can also be found on Austrian and red pines. Crawlers
occur in late June and July. Heavy feeding by this insect on pines
produces sufficient honeydew for the sooty mold fungi to grow on.
Sooty mold will turn the plant black. The adult female may produce
500 crawlers. The adult males can fly but not feed. This scale has
only one generation per year and prefers young trees to older trees.
Check with your local land grant university (Cooperative) Extension Service for recommended insecticide. Spray when Vanhoutte spirea is blooming. Second spray needed when hills of snow hydrangea blooms are turning from white to green and a third spray 7 to 10 days after the 2nd spray. A summer oil may discolor the needles.
Written by James Schuster, Extension Educator, Horticulture, and reviewed by Dr.Philip L. Nixon, Extension Specialist-Entomology, Department of Natural Resources and Environmental Sciences University of Illinois at Urbana-Champaign.