Scientists develop glue against pest insects

Damage to onion leaves by thrips. Special insect glue can help agriculture in combating pest insects. – Photo: Peter Roek

Researchers from Dutch universities in Wageningen and Leiden have developed a sticky substance that protects crops from pest insects like thrips.

In the search for alternatives to chemical crop protection, scientists from Wageningen UR and Leiden University took inspiration from nature, reports Wageningen UR. They developed a sticky substance to combat insects.

This was modeled after the carnivorous sundew plant, which has glandular hairs that secrete a sticky substance to trap insects. “We wanted to replicate that substance to protect our plants and crops in a natural way,” explains Thomas Kodger, Associate Professor of Physical Chemistry and Soft Matter at Wageningen UR.

Research on adhesive against pest insects focused on thrips

The researchers focused their method on a common agricultural pest: thrips. They created a sticky substance from rice oil waste by blowing air over it and then grinding the substance into small particles in a type of blender. This process produces droplets about a millimeter in diameter, which are as sticky as duct tape. These droplets are about the same size as thrips.

By capturing thrips in this way, crops are less susceptible to fungal infections, the researchers report. They published their findings in the scientific journal PNAS. In addition to thrips, other insects such as the spotted-wing drosophila in cherry cultivation could potentially be controlled in the same way. Since the droplets are very small, they are not harmful to other beneficial insects like bees and bumblebees.

Reducing chemical control

The insect glue not only has the advantage of contributing to the reduction of chemical control, but insects are also unlikely to develop resistance to this method, Kodger expects. “Insects have already evolved to avoid sticking to things, for example by having hairs and a bumpy surface,” he explains. “One of the few ways they could still escape this sticky trap is by enlarging their entire body.”

The substance can be sprayed in the same way as other agricultural agents. After spraying, it remains on the leaves for three months. There may be residues left on crops, but these are not harmful to health. The researchers are still investigating whether and to what extent the insect glue affects the soil.