Chapter 21

Managing Vineyard Insect and Mite Pests

Japanese Beetle

The Japanese beetle (Popillia japonica) is one of the most visible and most destructive feeders of grape vine foliage (See Figure 21.19).

Symptoms

Adult beetles feed on leaves only, concentrated on the upper part of the canopy, and occasionally the berries. Vines with tender vegetative parts are most susceptible to Japanese beetle attack, as are vineyards adjacent to pasture or sod fields.

Life Cycle

Japanese beetles over winter as larvae in the soil. In the spring when the soil begins to warm, larvae move toward the surface where they continue to feed and pupate. New adult beetles emerge from the ground in late spring and begin feeding on young leaves, especially those that are exposed to full sunlight.

Monitoring

Commercially available attractant traps are available for monitoring this pest. However, these beetles are easily detected while walking through the vineyard by observing the feeding damage and by seeing the beetles.

Pest Management

Cultural Practices

Many vineyards have sodded, row middles, which is done for good management reasons, but it also creates ideal conditions for Japanese beetles to lay eggs since they prefer to lay eggs in mown grass and in moist soil.

Applying Control Materials

Insecticides are usually applied when feeding is apparent on most vines and skeletonized leaves are found. Spot treatment is adequate in some cases.

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