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 22.19).
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.
Cultural Pest Control
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.
Biological Pest Control
Two species of tiphiid wasps (Tiphia vernalis and T. popilliavora) have been introduced to control Japanese beetle. The female wasp digs into the soil, paralyzes a beetle larva by stinging, and then deposits an egg on the larva. When the egg hatches, the emerging wasp larva consumes the host larva.
Biorational Pest Control
Microbials
Bacillus thuringiensis and Bacillus papillae are two microbial insecticides that can be used to control larvae, but they must be ingested to be effective. When the larvae eat the spores, the spores germinate in the larvae’s gut and enter the bloodstream.
Minerals
One mineral insecticide used to control Japanese beetle is Surround (kaolin).
Chemical Pest Control
There are several insecticides labeled for use against Japanese beetles on grapevines all of which are roughly similar in efficacy but vary in impact of beneficial arthropods like predatory mites. Insecticides to control Japanese beetle include Sevin (carbaryl), Assail (acetamiprid), Imidan (phosmet), Avaunt (indoxacarb), Brigade (bifenthrin), and Danitol (fenpropathrin). Insecticides used for controlling Japanese beetles in vineyards are presented in Appendix K, Insecticides Registered for Use in Vineyards.
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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