The Netherlands develops a new plant-derived insect-trapping adhesive

Drosera rotundifolia has a delicate appearance and leaves covered with glandular hairs, which are covered with mucus and can feed on insects. Wageningen University and Leiden University in the Netherlands have teamed up to develop an innovative insect catcher. They use vegetable oil as a base, allow it to oxidize, turn it into a thick, sticky liquid, and then spray it on the leaves, mimicking the slime droplets of insect-eating plants such as sungai, to catch small pests.

Thijs Bierman, a PhD student at the Leiden Institute of Biology, and his colleagues developed an insect-catcher made from vegetable oil, based on the idea of sunwort. They sprayed the goop on leaves to see if they could catch the western thrips (Frankliniella occidentalis). The tiny pest can harm more than 500 types of vegetables, fruits and ornamental crops.

"We managed to trap the Western thrips," Bierman said. The bigger the droplets, the better." 

Oily droplets can stay sticky for weeks, The Guardian reported. Tests have shown that more than 60% of thrips can be captured within two days.

Thomas Kodger, associate professor at Wageningen University's Physical Chemistry and Soft Matter Laboratory, noted that the current experiments focused on the western thrips, but it could be used on other pests in the future. For example, the Suzuki fruit fly.

Unlike chemical pesticides, he explained, adhesives must be large enough for insects to break free of the goo. However, changing body shape requires long-term generational evolution, which only occurs when adhesives are applied on a large scale. In contrast, with the application of chemical agents, the insect body can develop resistance in a short time, resulting in the failure of the agent.

The principle of adhesive spray is similar to that of slime paper, but the two are slightly different. Kodger says slime paper can't be sprayed, and it catches pests, but it also catches pollinators. The new slimy droplets are so small that they don't trap bees.

He says the adhesive can stick to the leaves for up to three months. Farmers can spray the adhesive in advance to avoid the adhesive remaining on the produce when it is sold. If the adhesive remains on the produce, consumers can wash it with water and detergent at home. It's yellow, which means consumers can tell if it's been washed.

Kodger explains that the adhesive is made from a base of cooking oil, and even a small amount is not harmful if you accidentally eat it. But scientists will have to do more research to be sure. In addition, they will continue to study the rate at which adhesives break down in the soil and their impact on the environment.