Stored Grain IPM

Project Title: Effectiveness of Spinosad on stored product insects.

Investigators: Bh. Subramanyam, Carl Reed, and Frank Arthur

Objectives: To characterize the fate and efficacy of Spinosad, a reduced-risk bacterial pesticide applied to hard, red winter wheat stored in bins.

Methods: Wheat stored in 1,000 bushel bins will be treated with Spinosad at 0, 1 and 3 ppm (mg of Spinosad/kg of wheat). Treated and untreated wheat will be sampled over time and residues of Spinosad measured in germ, bran, and endosperm fractions. Grain will be sampled for insects in the field. Samples brought to the laboratory will be assayed with insects. Residue breakdown and efficacy against insects at three temperatures and moisture contents will be determined in the laboratory. Several classes of wheat will be treated with Spinosad to determine influence of wheat class on insect susceptibility to Spinosad.

Impacts: Laboratory study conducted in 1998 indicated that Spinosad was very effective against lesser grain borers, rice weevils, Indianmeal moth, red flour beetles and sawtoothed grain beetles. This product appears to be a suitable replacement to the organophosphates malathion, actellic, and reldan, which are at risk of being cancelled under the 1996 Food Quality Protection Act. If found to be effective under field conditions, Spinosad could be a suitable product worthy of consideration for an Environmental Protection Agency (EPA) registration.