The Netherlands uses new science-backed weapons against oak processionary moth

A new trial will show how the dangers of the insect can be limited in an environmentally friendly way

Ten locations in The Netherlands have recently participated in a new trial, aimed to limit the population of the oak processionary in an environmentally friendly way. The invasive insect, which causes significant damages to oak leaves, but can also irritate human skin, will be limited through the so-called mating disruption. As its name suggests, the method influences mating behaviour, and its main advantage lies in the fact that, reportedly, there are no negative effects for other species.

Science against nature

Mating disruption in this case is a very simple process: pheromones, chemicals that act like hormones, are applied to the oak trees. This disrupts insect mating because the male butterflies can no longer find the females. As a result, fewer female processional butterflies are fertilized and fewer caterpillars appear, which leads to the gradual reduction in their population.

The pheromone is packaged in capsules and applied to the trees using a tool similar to a paintball gun. This technique is known to have successfully worked in France and Spain for the control of the pine processionary caterpillar.

Independent researchers and scientists at the University of Sweden have developed this method. The aim is to reduce the number of oak processionary caterpillars without adverse effects on other animals, plants, the environment and public health. Operations are being monitored and results are expected in November 2023.

In 2020, this method was applied in the Netherlands on a trial basis at 8 locations and showed positive results, local media report. However, it also proved labour-intense and expensive. Now, a new set of experiments is set to define whether the process can happen with fewer resources, making it cheaper and more practical.

The oak processionary caterpillar can be a source of disturbance for people, too. The caterpillar's stinging hairs can cause itching, pain and irritation to the skin, eyes, respiratory tract and gastrointestinal tract.