Why is insect pest management important to grape production?
Along with disease and weed management, successful grape production in Georgia relies on effective insect pest management. Insect pests can cause fruit loss, foliar damage, root and trunk girdling, and vector diseases. For many insect and arthropod pests, such as grape flea beetles (Altica spp.) and mites (e.g. Tetranychus urticae Koch), producers can evaluate the pest problem as it develops and determine if damage is significant enough to warrant pesticide application. As such, grape pests, the damage they cause, and their activity periods need to be recognized so that populations can be monitored at the appropriate time of the season to determine if insecticide applications are warranted. Avoiding unnecessary sprays will help prevent outbreaks of secondary pests, particularly mites, that are normally managed by an assortment of natural enemies. However, in the southeast there are also several “key” insect pests that will likely need to be managed on an annual basis.
For example, disease vectoring insects, such as leafhoppers/sharpshooters (Hemipter: Cicadellidae) that vector Pierce’s disease and fruit flies (Diptera: Drosophilidae; particularly Drosophila suzukii) that spread sour rot across berries and clusters, can be especially destructive to fruit quality and production. Additional pests, such as Japanese beetles (Popillia japonica) that feed heavily on leaves and grape root borer (Vitacea polistiformis) that feeds internally on the roots and the crown, can significantly reduce the photosynthetic ability and overall productivity of vines, respectively.
Each of these pests affects grapevines differently but can cause significant damage if they aren’t identified and stopped at the earliest signs of feeding. However, muscadine (Vitis rotundifolia) and Pierce’s disease tolerant hybrid wine grape cultivars (e.g. Blanc du bois, Lamonto) can help reduce reliance on systemic insecticides for leafhopper/sharpshooter management. Accurate insect identification and understanding of grown vine cultivars are essential in any pest management program. Careful and timely monitoring of grapes and good cultural practices will aid in effective management practices and reducing unnecessary insecticide applications. As such, extension personnel at the University of Georgia will continue to research and implement innovative monitoring and management tactics for insect pests in southeastern grape production.