Association of entomophilic rhabditoid nematode populations with natural control of first-instar larvae of the grape root borer, Vitacea polistiformis, in concord grape vineyards

Four Concord grape vineyards in Georgia were examined to determine the levels of infestation by the grape root borer, Vitacea polistiformis. Additionally, the soil at each vineyard site was assayed to determine relative levels of entomophilic rhabditoid nematode activity. An inverse correlation was shown to exist between severity of V. polistiformis infestation and activity of the entomophilic rhabditoid nematode fauna in the vineyard soils. Laboratory and field bioassays determined the susceptibility of first-instar grape root borer to the entomophilic rhabditoid nematode, Neoaplectana carpocapsae. This insect-nematode interaction was posited as a mechanism of natural control of grape root borer populations. Augmentation of entomophilic rhabditoid nematode populations during the critical period of oviposition and eclosion is suggested as a preventative control technique for V. polistiformis.