The insect glue, produced from edible oils, was inspired by plants such as sundews that use the strategy to capture their prey. A key advantage of physical pesticides over toxic pesticides is that pests are highly unlikely to evolve resistance, as this would require them to develop much larger and stronger bodies, while bigger beneficial insects, like bees, are not trapped by the drops.
The drops were tested on the western flower thrip, which are known to attack more than 500 species of vegetable, fruit and ornamental crops. More than 60% of the thrips were captured within the two days of the test, and the drops remained sticky for weeks.
Work on the sticky pesticide is continuing, but Dr Thomas Kodger at Wageningen University & Research, in the Netherlands, who is part of the self defence project doing the work, said: “We hope it will have not nearly as disastrous side-effects on the local environment or on accidental poisonings of humans. And the alternatives are much worse, which are potential starvation due to crop loss or the overuse of chemical pesticides, which are a known hazard.”
The issue is that sticky traps are non-specific. Any insect the size of a trip can be trapped. Then when predators are attracted to all the free food, they are potentially stuck or damaged as well.
Thrips are also one of the easiest species to control using predatory species.