ABSTRACT

This study reports on differences in means and variances of pest damage, insecticide use, and pest control costs between Bt and non-Bt acreage using state-level data. Some statistically significant differences are as follows. Insecticide applications for both target pests and all pests were lower on Bt acreage. Yield losses from target and all pests were lower on Bt acreage. The variance of yield losses from target pests was lower for Bt cotton. The hypothesis that means or variances of overall pest control costs, including Bt fees, were equal on Bt and non-Bt acreage could not be rejected. Results should be treated with caution because state-level data represent “uncontrolled” experiments subject to confounding influences.