| Popis: |
Transgenic cotton lines expressing an insecticidal protein produced by a modified crylA(c) gene from Bacillus thuringiensis kurstaki (i.e., Bollgard Gene, Monsanto Company) were planted 1 May near College Station, Texas. Field plots were 4 row (40 inch centers) X 30 ft. Treatments (i.e., cotton lines) were arranged in a split plot RCBD and each plot replicated was 6 times. The main plot was lepidopteran control (i.e., unsprayed or sprayed with Karate (0.03 lb[AI]/acre) to suppress tobacco budworm, bollworm and other lepidopteran pests) and subplots were 6 cotton lines. Plots for lepidopteran suppression (with a conventional foliar insecticide) were sprayed on 8, 15, 24 Jul, 3, 10, and 18 Aug with Karate using a backpack CO2 powered sprayer and a 2-row handheld spray boom. The entire test was planted with in-furrow insecticide and oversprayed as needed in season for control of insect pests, such as thrips, aphids, boll weevil and cotton fleahopper. Efficacy of transgenic Bollgard cottons against target lepidopteran pests was determined by examining 20 flower buds and 20 bolls per plot on 8, 15, 24 Jul, 3, 10, and 18 Aug for bollworm/tobacco budworm feeding injury, and taking seedcotton yields/plot. Supplemental soil moisture was provided as needed by furrow irrigation during the season, usually within 48-h following a lepidopteran control application. The plots were handharvested (60 ft from middle 2 rows). |
