Evaluation of Bacillus Thuringiensis Technology Against Helicoverpa Populations in Cotton Varieties Grown in the Upper Coastal Bend of Texas

A study was conducted during the 2012 crop season to evaluate the Bacillus thuringiensis (Bt) genetically modified cotton in selected varieties grown in the Upper Coastal Bend of Texas and record its effect on subsequent Heliothine populations. DeltaPine1048B2RF, FiberMax9058F, FiberMax1740B2F, and Phytogen499WRF were select for this evaluation. Data was randomly collected on the number of plants within a 10 ft. row at 12 and 30 days after planting (DAP). Additional data was gathered on the number of beneficial insects, bollworm eggs, and bollworm larvae on 25 random plants, as well as observing 25 squares for bollworm damage, during 64, 71, and 78 DAP. Beneficial insects observed consisted of lacewing larvae, lady beetles, spiders, and minute pirate bugs. The plant stand data at 12 DAP were not statistical different between varieties until 30 DAP. Significant differences were observed in the total number damage squares at 64 DAP only. There were no significant differences for the amount of Helicoverpa zea eggs, larvae, and beneficial during the entire study. Only two larvae were seen in the variety FiberMax9058F, both were small and seen on separate days. However, it should be noted that the participating grower did overspray these plots in between the 64 and 71 DAP data collection dates with a synthetic pyrethroid, which may have had a mitigating effect on subsequent Helicoverpa zea populations, egg lays and beneficials.