Resistance to conventional pesticides — among insects, weeds or microbial pathogens — is common on farms worldwide. CropLife International, an industry association based in Brussels, supports efforts that have counted 586 arthropod species, 235 fungi and 252 weeds with resistance to at least one synthetic pesticide (see ‘The rise of resistance’). And that’s just the cases that scientists have formally identified and recorded.
For several decades, the agrochemical industry has simply rolled out new chemicals to replace the old ones. But for many crops, the pipeline is drying up. The rate of discovery of pesticides has “gone almost to zero in the last ten years or so”, says Sara Olson, a senior research analyst at Lux Research in Boston, Massachusetts, which specializes in emerging technologies. New chemicals are difficult and expensive to find and develop. And once one is in use, pests will soon develop resistance to it, unless its application is carefully managed.
So scientists are pursuing alternatives that may reduce or replace synthetic pesticides. They are particularly interested in biological solutions, including microbes, genetic engineering and biomolecules. Even major chemical companies see enough promise to invest in the work. That doesn’t spell the end of synthetic pesticides, but it could help to slow the spread of resistance. Some approaches might also help farmers to reduce costs, protect workers and please a public that is increasingly wary of synthetic chemicals. See more