Early-Season Pests of Soybean in the United States and Factors That Affect Their Risk of Infestation

Soybean faces potential economic damage from a wide variety of early-season invertebrate pests. The objective of this article was to determine the extent and intensity of nine early-season soybean insect pests targeted for control by insecticidal seed treatments in the United States and to identify various management options for them: bean leaf beetle (Cerotoma trifurcate Förster, Coleoptera: Chrysomelidae); grape colaspis, Colaspis brunnea (F.) (Coleoptera: Chrysomelidae); leafhoppers (Hemiptera: Ciccadellidae); seedcorn maggot, Delia platura (Meigen) (Diptera: Anthomyiidae); soybean aphid (Aphis glycines Matsumura, Hemiptera: Aphididae); threecornered alfalfa hopper, Spsistilus festinus (Say) (Hemiptera: Membracidae); thrips (Thysanoptera: Thripidae); white grubs (Coleoptera: Scarabaeidae); and wireworms (Coleoptera: Elateridae). Seedcorn maggot, white grubs, and wireworms have been limited to a relatively small proportion of soybean fields with readily defined factors regarding their risk. However, questions about the pest status of the other six pests were identified. Bean leaf beetle, which vectors Bean pod mottle virus to soybean, has been present across major soybean-production regions, but frequency and proportion of soybean fields that economically impacted is not adequately documented. The impact of threecornered alfalfa hopper and thrips on soybean productivity varied within regions, but specific reasons for the variation were unclear. Early-season management of grape colaspis and leafhoppers has been infrequent, but factors that promoted economic injury and the need for management in specific fields were undetermined. Although early-season management of soybean aphid has not proven feasible for individual fields, questions remain regarding its management in fields near overwintering stands and the possibility for areawide suppression.

CROP IMPROVEMENT THROUGH INDUCING MUTAGENESIS IN VIVO USING COLCHICINE ON COWPEA (Vigna unguiculata L. Walp)

Colchicine treatments of 0.005% and 0.01% either in distilled water or in hydrogen peroxide 3% were caused temporary leaf shape changes on cowpea. Treatment of colchicine in hydrogen peroxide 3% resulted in green pod color change to purple however treatment of just hydrogen peroxide 3% and colchicine in hydrogen peroxide 3% caused 8.8-10.7% dwarf cowpea. As a preliminary data, we also observed that cowpea crops grown from seeds treated with colchicine in distillate water attacked by bean leaf beetle much earlier compare to the treatment with colchicine in hydrogen peroxide 3%.