Chapter 21

Managing Vineyard Insect and Mite Pests

Western Grapeleaf Skeletonizer

Western grapeleaf skeletonizer (Harrisina brillians) is a pest of grapes that periodically defoliates vineyards. It is a native of the southwestern United States and northern Mexico.

Symptoms

The larvae of the western grapeleaf skeletonizer feed on the lower leaf surface leaving a brown, necrotic, skeletonized leaf tissue. This gives leaves a whitish paper-like appearance; eventually the entire leaf turns brown.

Life Cycle

Pupae pass the winter in cocoons on the ground in debris. In late spring, adult moths emerge and eggs are deposited in yellow clusters on lower leaf surfaces.

Monitoring

The moths are active during the day and so will be very easy to detect when populations are significant (See Figure 21.23).

Pest Management

Cultural Practices

During the dormant season remove mummy clusters and debris on the ground.

Applying Control Materials

In areas where western grapeleaf skeletonizer does occur, granulosis virus usually keeps populations below economically damaging levels.

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