University of Illinois Extension

University of Illinois Extension

Hort Answers

Insect Damage

Pine Tortoise Scale
Toumeyella parvicrnis

Sooty mold grows on insect honeydew.
Sooty mold grows on insect honeydew.
2 (1 = rare 5 = annual)
3 (1 = very little damage 5 = plants killed)
Pine tortoise scale attacks mainly Scots and Jack pine. It can also be found on Austrian and red pines.

Plants Affected
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.

Life Cycle
Crawlers occur in late June and July. 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.

If necessary use a recommended insecticide. Spray when Vanhoutte spirea is blooming. A second spray is needed when Hills of Snow Hydrangea blooms are turning from green to white and a third spray 7 to 10 days after the 2nd spray. A summer oil may discolor the needles.

Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic