Efficacy Of The Bollgard Gene In Transgenic Cotton Lines Against Bollworm And Tobacco Bud-Worm, 1994

Abstract

Abstract Efficacy Of The Bollgard Gene In Transgenic Cotton Lines Against Bollworm And Tobacco Bud-Worm, 1994 Transgenic cotton lines expressing an insecticidal protein produced by the cryIA(c) gene (i.e., Bollgard Gene), or cryllA gene (Monsanto Co.) from Bacillus thuringiensis kurstaki and the nontransgenic parent line Coker 312, were planted 25 Apr near Corpus Christi, Texas. Field plots were 4 row (38 inch centers) X 30 ft. Treatments (i.e., cotton lines) were arranged in a split plot RCBD and each plot replicated 6 times. The main plot was lep-idopteran control (i.e., unsprayed or sprayed with Karate (0.03 lb[AI]/acre to suppress tobacco budworm, bollworm and other lepidopteran pests) and sub-plots were 8 cotton lines. Plots for lepidopteran suppression (with a conventional foliar insecticide) were sprayed on 29 Jun, 6, 14, and 20 Jul with Karate using a backpackCO2 powered sprayer and a 2-row handheld spray boom. The entire test was planted with in-furrow insecticide and oversprayed as needed in-season control of insect pests such as thrips, aphids, boll weevil and cotton fleahopper. Efficacy of transgenic cottons against target lepidopteran pests was determined by examining 20 flower buds and 20 bolls per plot on 28 Jun, 5, 12, and 19 Jul for bollworm-tobacco budworm feeding injury, and taking lint yields per plot. Supplemental soil moisture was provided by sprinkler irrigation during the season but not within 48-h following a lepidopteran con-trol application. The plots were hand-harvested (20 ft from middle 2 rows) and seedcotton ginned on a laboratory 10-saw gin.