Crop scientists at Rothamsted Research have found that an olive oil extract slows down the processes by which insecticide resistance builds up.
In simulated field experiments, plants sprayed with a mixture of SYN-A, a naturally derived synergist extracted from olive oil, and the pyrethroid insecticide lambda-cyhalothrin increased cabbage stem flea beetle (CSFB) mortality from 20% to 75% and reduced plant damage by at least 50% compared to lambda-cyhalothrin applications alone.
Scientists at Rothamsted Research and ApresLabs Ltd have demonstrated that SYN-A can restore the effectiveness of pyrethroid insecticides against CSFB, the most devastating autumn pest of oilseed rape.
The research reveals that combining SYN-A with lambda-cyhalothrin increases pest mortality such that using just 20% of the standard insecticide rate together with SYN-A achieved 2.2 times greater control than applying the full insecticide dose without the synergist.
Dr. Samantha Cook, who led the study explained: “CSFB is the number one insect pest for farmers right now due to their inability to control it using traditional insecticides, as the EU have banned neonicotinoid seed treatments and the beetles have developed resistance against the permitted pyrethroid insecticide sprays.
“This tiny beetle is threatening oilseed rape production throughout the UK and much of Europe.
“The industry badly needs alternatives, but these are some way off in the development pipeline.’’
SYN-A functions by inhibiting the action of cytochrome P450 and esterase enzymes.
These are key metabolic pathways that resistant insects use to break down insecticides.
Laboratory studies demonstrated that this natural compound effectively blocks these detoxification mechanisms in CSFB.
Dr. Graham Moores, founder of ApresLabs Ltd who discovered, developed and patented SYN-A said: “I have long felt that synergists should be utilised to a greater extent in agriculture.
“SYN-A is a natural extract that allows a reduction in insecticidal rates whilst still overcoming resistance problems, with the concomitant environmental benefits this brings.”
But there is a slight snag.
While the findings offer promise to control CSFB, it has also been shown in the laboratory that SYN-A, when mixed with lambda-cyhalothrin, similarly affected Microctonus brassicae, a beneficial wasp that naturally controls adult CSFB.
However, members of the Rothamsted group emphasise that these potential impacts highlight the importance of designing careful implementation strategies, including precision application outside peak parasitoid wasp activity and continued evaluation of other non-target effects.
The findings align with EU targets to reduce insecticide use while maintaining effective pest control.
By potentially allowing farmers to use 80% less insecticide while achieving superior control, SYN-A could represent a significant step toward more sustainable agriculture.
