The efficacies of selected Bt and non-Bt field corn hybrids were evaluated against artificial and natural field infestations of southwestern corn borer (SWCB), Diatraea grandiosella Dyar, and sugarcane borer (SCB), Diatraea saccharalis F. (Lepidoptera: Crambidae). The experiments were conducted at the Macon Ridge location of the Louisiana State University Northeast Research Station near Winnsboro, Louisiana during 1999 and 2000. Artificially infested experiments consisted of a split-plot design with 4 repetitions. Seed brands were used as whole plots and corn hybrids as subplots. Seed brands included Pioneer, Garst, and DeKalb seeds. Each subplot consisted of two rows (40 inches apart) and 25 ft in length. Analyses of borer injury to mid-whorl leaves, husk leaves and ear leaf sheath indicate a significant reduction in damage in all Bt-corn hybrids compared to non-Bt hybrid isolines. Experiments subjected to natural infestations of SWCB and SCB were designed as a RCB with 5 repetitions. Plots consisted of 16 rows (40 inches apart) and 45 ft in length. Hybrids included Bt corn Pioneer 31B13 and non-Bt corn Pioneer 3223. Incidence and intensity of damage caused by borers were significantly less in the Bt-corn hybrid as indicated by low numbers of injured plants per plot and low numbers of holes per plant in the Bt hybrid compared to the non-Bt hybrid. Yields collected from locally adapted Bt and non-Bt hybrids in experimental plots suggest that locally adapted Bt-corn hybrids offer the greatest potential for economic yield advantage but only when the SWCB and the SCB are the major pests of the corn crop.
Species 1: Lepidoptera Crambidae Diatraea grandiosella (southwestern corn borer)
Species 2: Lepidoptera Crambidae Diatraea saccharalis (sugarcane borer)
Keywords: Bt corn, Economic Analysis
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA