Evaluation of Different Varieties of Corn Against Corn Earworm, 2016

Selected varieties of corn were evaluated for control of corn earworm at Lee Farm in Hayward, MO, which is the field location for the Fisher Delta Research Center. The varieties tested included two non-Bt varieties as well as four with Bacillus thuringiensis (Bt) traits. DKC66-94RR2 is a Roundup Ready conventional variety of corn from DeKalb. DKC66-97VT2P is a DeKalb Corn with a VT DoublePro trait. P1319R is also a conventional variety from Pioneer. P1319HR features the Cry1F protein and is from Pioneer. P1319YHR contains the Cry1F and Cry1Ab proteins from Pioneer. The final variety, P1319VYHR, contains the Cry1F, Cry1Ab, and a vegetative insecticidal protein (Vip3A) from Bt. Corn was planted in 9 May. The test was arranged in an RCB design with four replicates. Individual plots were 13 × 20 ft and planted at a rate of 156 seeds per plot. Plots were sampled by collecting 10 ears from each plot randomly from the outer two rows and then measuring the number of damaged kernels per ear and the area of ear consumed in centimeters at dent stage, which occurred in 6 Sep, 120 days after planting (DAP). Data were subjected to ANOVA and means were separated using a protected LSD.

The ears of the conventional variety of corn, DKC66-94 RR2, showed significantly more damage than all other varieties when examining the kernels at the dent stage. The conventional corn had both more damaged ears and more damaged kernels at the time of assessment. When observing for damaged area on the ears, the conventional corn had significantly more damaged ears than all other varieties, with all other varieties being comparable at that stage. This research was partially supported by industry gifts of pesticide and seed.

Author notes