MSU Extension Integrated Pest Management

Oystershell scale

Insect

Oystershell scale

Lepidosaphes ulmi (L.)

Hemiptera: Sternorrhyncha: Diaspididae

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

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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.

• Crops Affected: apples, pears, plums

  Damage

  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.

  Management

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