Pest and Beneficials Search (search again)

Oystershell scale

Lepidosaphes ulmi (L.)
Hemiptera: Sternorrhyncha: Diaspididae

The adult female remains immobile under a small brown scale in the shape of an oyster shell (A) attached to the bark of branches. The white and oval eggs (B) are laid inside the scale and crawlers emerge in the spring during the petal fall stage of apple.


Most fruit-growing states and provinces in eastern North America and south through the mid-Atlantic states.


Attacks apple, pear, quince, plum, apricot. Small, dark brown scales clustered on bark or fruit (C), at times entirely covering it, causing cracks and a scaly appearance. Infested tree is weak, its foliage is undersized and specked with yellow.


Spray a delayed dormant oil when buds are showing green tissue but before pink bud.

Pest and Beneficials Search (search again)

The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the AgBioResearch, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.