Thousands of tons of insecticides are spewed on crops and farm animals worldwide, and these amounts are still growing because insects are increasingly developing resistance to the chemicals. Researchers at the Weizmann Institute of Science, in collaboration with scientists in Australia, have now found a way to  overcome a common form of resistance to widely used insecticides.  

Many of the universally used insecticides work similarly to nerve gas: they kill insects by blocking an enzyme called acetylcholinesterase, or AChE, which plays a crucial role in transmitting nerve signals. Insects become resistant to insecticides when there is a mutation in one of these enzymes. 

Dr. Nir London, of Weizmann’s Organic Chemistry Department and Prof. Colin Jackson of the Australian National University set out to search for molecules that would block this mutation, making crop-destroying pests vulnerable once again to insecticide. London used the computer algorithm he had developed for discovering small molecules that can block the activity of an enzyme by forming an extremely strong bond with its active site. 

“In effect, the compound reversed the resistance of blowflies to commonly used insecticides,” London says. “Our approach could be applied to eliminating many other pests.” 

The compound is expected to be non-toxic to humans and other mammals, even when applied at high concentrations. These findings may help drastically reduce the use of insecticides, cutting environmental pollution as well as the cost of insect control.