Protection of stored maize from insect pests using a two-component biological control method consisting of a hymenopteran parasitoid, Theocolax elegans, and transgenic avidin maize powder

The hymenopteran parasitoid, Theocolax elegans (Westwood), and transgenic avidin maize powder were tested to determine if their individual or combined use would protect stored grain from infestation by both internal and external insect pests. Small-scale tests were conducted in plastic jars containing 3 kg of nontransgenic maize. We tested treatments of 0.3% powdered avidin maize, the parasitoid wasp, and the combination of the parasitoid plus 0.3% powdered avidin maize. One pair each of Sitophilus zeamais Motschulsky, Tribolium castaneum (Herbst), and Cryptolestes ferrugineus (Stephens) was added to each jar. After 8 weeks, the entire contents of each jar were examined for adult insects. Control and avidin maize powders had no detrimental effects on the beneficial insect parasitoid T. elegans. The parasitoid suppressed populations of the internal feeder S. zeamais. The avidin maize powder treatment had no effect on S. zeamais because these larvae developed inside the maize kernels where no avidin maize powder was present. For S. zeamais, the combination treatment was not significantly different from the parasitoid treatment. In contrast, populations of the external feeder T. castaneum were not suppressed by the parasitoid but were suppressed by the avidin maize powder treatment. The parasitoid-avidin combination treatment produced the greatest percentage reduction for all three insect species and resulted in 78%, 94%, and 70% reductions in populations of S. zeamais, T. castaneum, and C. ferrugineus, respectively, when see front matter Published by Elsevier Ltd. jspr.2005.02.002 r reports the results of research only. Mention of a proprietary product or trade name does not constitute ation or endorsement by the US Department of Agriculture. ding author. Tel.: +1 785 776 2707; fax: +1 785 537 5584. ress: [email protected] (P.W. Flinn).