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Identifying and Treating Scale on Aspen Trees

Gray Scabs on Aspen Trunks: Likely Aspen or Oyster Scale

The clusters of tiny, grayish, aphid-sized bumps on your aspen trunks are probably the crawler stage of aspen scale or oyster scale. A photo would confirm, but the description fits. If the foliage looks healthy, the trees are not in immediate danger.

Control Options

Spray the trunks with an insecticide labeled for scale, such as Orthene (acephate).
Timing matters: target the mobile crawler stage before they settle and form protective covers.

No need to remove infected trees unless they’re heavily infested and declining. Treatment can preserve them.

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