Insects develop resistance by producing enzymes that block pesticides from working. It has long been known that a naturally occurring organic chemical called piperonyl butoxide (PBO) could inhibit these enzymes.
Previous research had tried applying it as a mix with pesticides, but without success - the pesticide was already deactivated by the time PBO had been absorbed through the insect's cuticle.
Graham Moores of Rothamsted Research and Robin Gunning from New South Wales Department of Primary Industries have now developed a way of encapsulating insecticide into crystals that dissolve after five hours, giving PBO time to act before the insecticide's active ingredient is released.
"It has worked on every pest we have looked at to date," said Moores. "I am very, very excited about it. It could have huge implications for control of resistant pests and for using less pesticide to control susceptible pests."
An agreement for applying the technology in horticulture has been made with Italian company Endura Fine Chemicals, the largest worldwide producer of PBO.
While agricultural crops such as cotton and sugar beet are likely to gain first from the development, Moores said UK horticulture could also benefit. "For instance, it worked extremely well on peach-potato aphid," he said.
All Comments
Pesticide encapsulation is not a new technology. The main benefit is to contain acute toxicity to a pesticide spray operator. However, a delayed active ingredient release will pose huge and incremental risks to people downwind of a spray, and to all life-forms exposed to contaminated soil and water. The addition of any catalyst will require new and full toxicology studies. Efficacy at lower doses on aphids indicates a lowering of the NOEL as well. I suspect that the Ethics Committee which approved of this controversial research did not include a toxicologist or a regulator.