Effect of imidacloprid seed treatment on infestations of wheat curl mite (Acari: Eriophyidae) and the incidence of wheat streak mosaic virus

The survival of wheat curl mites (Aceria tosichella Keifer) collected from Kansas, Montana, Nebraska, South Dakota, and Texas was evaluated in the greenhouse on 'Larned', 'TAM 107', and 'Karl 92' wheat, with and without imidacloprid seed treatment. The effect of imidacloprid on the incidence of wheat streak mosaic virus (WSMV) transmitted by Kansas wheat curl mites was evaluated in the field and greenhouse. No significant differences occurred in wheat curl mite populations on any of the cultivars with and without imidacloprid. However, more wheat curl mites from each of the six collections tended to infest imidacloprid-treated Lamed than untreated Lamed. In one greenhouse test, the incidence of WSMV was significantly less for imidacloprid-treated than untreated Lamed and TAM 107, but in two subsequent tests, no significant differences occurred In the field at Garden City, Kansas, no significant differences occurred in wheat curl mite populations or incidence of WSMV between imidacloprid-treated and nontreated Karl. 92. However, at Hays, imidacloprid-treated Karl 92 had significantly more wheat curl mites per spike than untreated Karl 92, but this did not affect the incidence of WSMV in the same plots. Results from both field and greenhouse tests indicated that imidacloprid seed treatment did not consistently control WSMV or its vector. However, imidacloprid may be useful in research with wheat curl mites and their transmission of WSMV to prevent aphids and other insects from contaminating experiments.