Managing Vineyard Insect and Mite Pests
Grape Root Borer
The grape root borer (Vitacea polistiformis) is native to the eastern United States and has been damaging vineyards in the southeastern United States for over 150 years. It has been declared the most destructive insect pest of grapes in many states including Georgia, North Carolina, Virginia, and Florida.
Symptoms
Larvae of the grape root borer will attack the larger roots of grapevines causing a decline in vine vigor and productivity (See Figure 22.13). Symptoms occur gradually and include yellowing of leaves, smaller leaves and berries, reduced shoot growth, vine dieback, and reduced yield.
Life Cycle
The life cycle takes 2 or possibly 3 years to complete, and almost all of this is spent as larvae feeding on grapevine roots. When mature, the larvae leave the root and tunnel to just beneath the soil surface where it makes a cocoon and pupate.
Monitoring
Pheromone-baited traps are recommended for monitoring adult moths. Traps are placed in, or on the edge of, a vineyard at the rate of one trap per acre. They should be put out beginning in early summer and monitored once a week until no moths are caught.
Cultural Pest Control
Under row weed control is important in managing this insect pest. Weed control decreases the number of oviposition (egg-laying) sites and provides an area under the trellis suitable for applying an insecticide.
Biorational Pest Control
Pheromones
An alternative method of control is to use biochemical insecticides such as pheromone rope ties to disrupt the ability of males to locate the female grape root borer. Ties are dispensed manually at a rate of 100 ties per acre.
Chemical Pest Control
Lorsban (chlorpyrifos) is used to control grape root borer. Insecticides used for controlling grape root borer in vineyards are presented in Appendix K, Insecticides Registered for Use in Vineyards.
Applying Control Materials
Effective chemical control involves a directed insecticidal spray to the base of the vine to establish an insecticide barrier on the soil surface. It is applied as a coarse spray to kill adults as they exit the soil and newl
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