Estimates differences in pesticide use between 1997 and 1998, with an econometric model controlling for factors other than GE crop adoption that may affect pesticide use. Because the results include only statistically significant differences in pesticide use by adopters and nonadopters, many relatively small differences in particular regions were not included, thus underestimating overall differences. Assessing change in pesticide use associated with adoption of GE crops is confounded by the same difficulties associated with pesticide use generally. Comparison of different mixes of pesticides involves evaluating tradeoffs between the amounts used and their environmental characteristics, primarily toxicity and persistence. Summary Statistically controlling for factors other than adoption of genetically engineered seeds allows an understanding of the likely impacts of marginal changes in adoption on yields, profits, and pesticide use.
Impacts vary with the crop and technology examined.
Increases in adoption of herbicide-tolerant cotton were associated with significant increases in yields and variable profits, but were not associated with significant changes in herbicide use. Increases in adoption of herbicide-tolerant soybeans were associated with small increases in yields and variable profits, and significant decreases in herbicide use. Increases in adoption of Bt cotton resistant to insects in the Southeast were associated with significant increases in yields and profits and decreased insecticide use. Links Some of these documents are in Adobe Acrobat format. You can download and get help using the Adobe Acrobat Reader to view and print these documents.