A University of Virginia economist has wrapped up the largest single study of the environmental effects of GM (genetically modified) corn and soybeans in the U.S. With help from economists at Kansas State University, Iowa State University and Michigan State University, Federico Ciliberto analyzed annual survey data from more than 5,000 corn and 5,000 soybean farmers over a 14-year span, 1998 to 2011.
Insect-resistant traits (Bt corn hybrids) were the only clear environmental winner — the study showed they decreased insecticide use by farmer adopters by 11.2%. Ciliberto attributed part of this success to the use of refuges in corn fields, which help slow the development and spread of Bt-resistant insects.
Herbicide-resistant traits performed less admirably. Although corn farmers using these traits reported a drop of 1.3% in herbicide use over 13 years, soybean farmers who adopted these traits saw a 28% increase in herbicide use. In the last five years (2006 to 2011), both corn and soybean farmers’ herbicide use increased. The problem? The widespread development of herbicide-resistant weeds, in particular glyphosate-resistance.
Click here to read full article: Genetically Engineered Crops and Pesticide Use in U.S. Maize and Soybeans
Emily Unglesbee can be reached at firstname.lastname@example.org
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