USE OF FEEDING STIMULANTS TO ENHANCE INSECT GROWTH REGULATOR-INDUCED MORTALITY OF FALL ARMYWORM (LEPIDOPTERA, NOCTUIDAE) LARVAE

The mortality of fall armyworm (FAW), Spodpoptera frugiperda (J. E. Smith), larvae was significantly increased when they fed on leaves of southern pea Vignaunguiculata [L.] that had been treated with either of two insect growth regulators (IGRs) (RH-5992 and diflubenzuron), in combination with Konsume(R),a cottonseed flour based insect feeding stimulant. Larval mortality was increased 2 and 3 days after treatment when Konsume (10% solution) and RH-5992 at 0.001 and 0.01% active ingredient [AI] were applied in combination, respectively. Similarly, a 10% solution of Konsume enhanced the effects of diflubenzuron (0.01% AI) on FAW larvae 4, 6, and 7 days after treatment. A 5% solution of Konsume mixed with diflubenzuron (0.001% AI) resulted in significantly greater fall armyworm larval mortality 2-5 days after treatment compared with diflubenzuron alone. The feeding stimulants Nu-Lure(R), Coax(R) and Konsume all performed similarly against FAW larvae when mixed with either RH-5992 or diflubenzuron. However, Nu-Lure and Coax mixed with the IGRs did not significantly increase fall armyworm mortality above that caused by the IGRs alone. The simultaneous use of a feeding stimulant, such as Konsume, may provide an effective tool to increase toxicant activity of RH-5992 or diflubenzuron, and decrease the time needed to effect death of fall armyworm larvae.