A Threat to Organic Agriculture Bt crops also pose a threat to organic agriculture. Organic farmers have long used the Bt toxin in a natural spray as a component of an integrated pest management scheme. The spray targets specific pests and is non-toxic to mammals. However, plants that continually produce the Bt insecticide will exert strong selective pressure on insects to develop resistance to the insecticide. As insects evolve resistance to Bt toxins, organic farmers will be stripped of one of their most valuable tools.
Many scientists believe that efforts to slow the development of resistance in pests are ineffectual.
A recent article in the journal Science found that a common pest of cotton was able to build up resistance to the Bt plant pesticide very quickly. 1 Chevre et al, 1998.