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Fig. 4. Comparison of Bt and non-Bt corn hybrids for the presence of corn earworm (CEW) larvae, or damage from insects at Urbana and Monmouth, IL, in 2000 and 2001. Widstrom ratings for corn earworm damage were recorded as 0 = no damage, 1 = damage to silks only, 2 = kernel damage to 1 cm beyond the ear tip, and 3 = kernel damage to 2 cm beyond the ear tip. Guthrie ratings for European corn borer (ECB) damage were recorded as 0 = no visible leaf feeding, 1 = a small amount of pin or fine shot-hole injury on a few leaves, 2 = a small amount of shot-hole injury on a few leaves, and 3 = shot-hole injury common on several leaves. Lowercase letters above columns designate differences at 
= 0.05 between Bt and non-Bt hybrids within insect observations.
