China, the top cotton-producing country in the world at 16 billon pounds per year, first introduced Bt cotton in 1997. For the first decade, Bt cotton was highly effective against both cotton bollworm and pink bollworm in China. Recently, however, early signs of resistance to Bt cotton have been detected in caterpillars collected from the field, and growers may have to increase the use of insecticide if resistance evolves further....
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