Managing Vineyard Insect and Mite Pests
Grape Rootworm
The grape rootworm (Fidia viticida) is a native species of leaf beetle that occurs from the Atlantic Seaboard states to North Dakota, Nebraska, Kansas, and Texas. This pest appears sporadically and does not require treatment every year.
Symptoms
The most noticeable damage is the characteristic chain-like feeding pattern caused by the adults on the leaves (See Figure 22.15). This feeding damage is similar to that made by grape flea beetle larvae.
Life Cycle
Larvae of this beetle overwinter in the soil among grape roots. In the spring the beetle larvae pupate near the surface when grapes bloom.
Monitoring
Adult beetles feed on the upper surface of the leaves and can feign death when disturbed; therefore, they have the tendency to fall off vines. Look for slit-like feeding cuts made by adult beetles on leaves.
Cultural Pest Control
Pupae may be destroyed by shallow cultivation of soil until adults emerge in late spring.
Chemical Pest Control
Standard chemicals for controlling grape rootworm include Imidan (phosmet), Sevin (carbaryl), and Mustang-Max (dimethylcyclopropane carboxylate). Insecticides used for controlling grape rootworm in vineyards are presented in Appendix K, Insecticides Registered for Use in Vineyards.
Applying Control Materials
Control of the grape rootworm is easily accomplished through insecticide treatments directed at the adult stage when chain-like feeding symptoms appear in the vineyard. Treatments applied too early may not persist long enough to kill rootworm adults during the 3- to 4-week period when most emerge from the soil.
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