Corn Earworm Control, Othello, 1976

Eight chemical and microbial treatments were applied to 'Jubilee' sweet corn using fixedwing aircraft. Four applications were made at 5-day intervals beginning September 2 , 1976 (10% silk). Plots were one acre each, replicated four times in randomized blocks. Fifteen days after the last application, 50 ears were sampled from the center of each plot. Each ear was checked for earworm damage and the number of ears with one or more living earworms was also recorded. Extent of damage was rated for length using an index of 1 to 5 where 1 = 0 - 0 . 5 cm, 2 = 0 . 5 - 1 cm, 3 = 1 - 2 cm, 4 = 2 - 3 cm, and 5 = > 3 cm in length and for circumference where 1 = 1 - 2 kernels, 2 = up to 1/4, 3 = up to 1 / 2 , 4 = up to 3 / 4 , and 5 = up to entire circumference. Materials tested were also evaluated for toxicity to honey bees, using an index of 0 to 5 where 0 has no hazard, 1 having a short residual hazard, and 5 a long residual hazard.