Management of corn earworm using Bt corn hybrids, 2024 Open Access

Management of caterpillars and rootworms in corn has been improved by planting transgenic Bt (Bacillus thuringiensis) hybrids expressing Bt proteins. These Bt traits, whether used alone or in combination, can prevent higher levels of damage from pests, such as the corn earworm, Helicoverpa zea (Boddie). On 17 April 2024, field corn varieties were evaluated for the performance of Bt corn hybrids against corn earworm at the West Florida Research and Education Center, University of Florida, Jay, Florida. Plot size was 4 rows (12 ft wide) by 340 ft long at 2 seed/ft. (approximately 30,000 seed/acre) under conventional tillage. During the R3 growth stage, a total of 15 ears per plot randomly selected were sampled to determine the performance of Bt hybrids against corn earworm. The total number of corn earworms per ear, the number of corn earworms on 3rd or greater instar per ear, and the kernel area consumed in cm² per ear were evaluated. On 26 August 2024, yield data was collected from the middle 2 rows of each plot. Feeding on unfertilized and/or aborted kernels at the ear tip was not considered. All data, except yield, were subjected to Generalized Linear Mixed-Effect Models (GLMMs) followed by Tukey’s LSD test.

Trecepta hybrids (CP5363TRE/RIB, CP5682TRE/RIB, CP5760TRE/RIB, CP5893TRE/RIB, CPX23119A/TRE, DKC66-06, and DKC69-99) showed no detectable corn earworm larvae or injury, making them significantly more effective in controlling pest pressure compared to the VT Double Pro hybrids (Table 1). The corn varieties DKC117-78, DKC68-35, and DKC70-45 had higher larvae counts and area consumed. Hybrids with yields exceeding 200 bu/acre included CP5678VT2P/RIB (226.1 bu/acre), DKC70-45 (207.9 bu/acre), CP5363TRE/RIB (202.4 bu/acre), and CP5893TRE/RIB, which had the highest yield at 229.4 bu/acre.¹

Footnotes