Agriculture: Walnut Pest Management Guidelines

Distinguishing Scale

Names link to more information on identification and management.

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Frosted scale
Frosted scale
Identification tip: Frosted scales overwinter as brownish, flat nymphs.

Walnut scale
Walnut scale
Identification tip: After the first molt, males begin to develop an elongated covering, often clustered in daisy-shaped groups beneath the margin of the female’s round cover.

European fruit lecanium
European fruit lecanium
Identification tip: Look for legless, immobile, yellow insects on twigs. Older nymphs may have brown markings and a distinct center ridge.

San Jose scale nymphs
San Jose scale (nymphs)
Identification tip: The four round, dark scales in the center are the black cap stage, the most common overwintering form. The earlier white cap stage is to left.

Text Updated: 12/07
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