Evaluation of the Entomogenous Nematode Neoaplectana carpocapsae (=Steinernema feltiae) Weiser (Rhabditida: Steinernematidae) and the Bacterium Bacillus thuringiensis Berliner var. kurstaki for Suppression of the Artichoke Plume Moth (Lepidoptera: Pterophoridae)

Abstract

The entomogenous nematode Neoaplectana carpocapsae Weiser and the bacterium Bacillus thuringiensis var. kurstaki were evaluated in the field against the artichoke plume moth infesting artichoke in its vegetative growth phase. In general, nematode concentrations ≥ 1,000 nematodes/ml were highly effective against older larvae when applied to artichoke plants to runoff. Used at 2,000 nematodes per ml, the nematode gave 100% control of 3rd and 4th instars 15 days after treatment, and its residual effect, evaluated 24 days after treatment, was greater than that of a commonly used insecticide, methidathion. Although B. thuringiensis var. kurstaki used at the rate of 19.6 billion International Units/ ha gave significant larval control, its efficacy was numerically but not significantly lower than that of methidathion. Combination of the nematode and B. thuringiensis var. kurstaki did not result in significantly greater control than that achieved by the nematode used alone. The moist micro habitat and moderate temperatures during most of the artichoke-growing season in the fog belt region of the central coast of California, together with the tunneling habit of the host larvae, suggest that the nematode could be successfully used as a biological control agent against the artichoke plume moth larvae infesting the vegetative shoots.