European elm scale—Gossyparia spuria

The European elm scale occurs only on elm trees. The mature female is a dark red, brown, or purple oval surrounded by a white cottony wax fringe on the sides of the body. <see image>


Scales encrust bark at the crotches of twigs and on the lower surface of limbs. In spring and summer, some crawlers settle and feed on the underside of leaves. Honeydew and blackish sooty mold may occur on the plant. Branches may die back.


  • TreeAzin is injected under a tree’s bark, directly into the conductive tissues, and moves upwards with the flow of water and nutrients.
  • BioForest has developed the EcoJect System, a tree microinjection system for the application of systemic pesticides into high value trees (US Patent 7,114,289) that we at Rossco’s use.
  • With the EcoJect System:
    • Canisters are loaded with TreeAzin and sealed under pressure.
    • Small injection holes (15/64″) are drilled into the tree (3/4 – 1″).
    • Nozzles are inserted and secured in the injections holes.
    • TreeAzin loaded canisters are mated with the nozzles, beginning the injection.
  • TreeAzin is formulated to inject quickly into ash (avg. 15 – 30 min. / tree) and translocates rapidly throughout the tree (approx. 48 hrs).
  • The TreeAzin dosage and number of injection sites per tree depends on the insect being controlled and on the health and size of the tree.

Think your tree(s) has European Elm Scale? Give us a call today for a health valuation and to discuss treatment options.

Elm Scale - Mature Female