Oak processionary caterpillars preparations

Oak processionary caterpillar season is upon us again. You may find hairy caterpillars on oak trees during May, June and July. After contact with the hairs of this caterpillar, symptoms such as itching, skin rashes, irritation to the eyes or respiratory tract may occur.

Biological control method

This year, the municipality has again decided to use a biological control method. The product in question is Xentari. Xentari is not harmful to humans or the environment. The caterpillar’s natural predators, such as parasitic wasps and flies, bees, and mites, are not affected by the product. In addition to being environmentally friendly, the product also acts as a preventative measure. Xentari is applied when the young caterpillars climb into the trees to feed. At this stage, the caterpillars have not yet developed their stinging hairs and are not yet harmful.

Implementation

We expect to begin the treatment starting in week 18 (the week of April 27). The oak processionary caterpillar control will be carried out by a specialized company under the supervision of the municipality. A second treatment within approximately 10 days may be necessary. Due to the contractor’s workload, the work may also take place in the evening and/or at night. The municipality does not control caterpillars in forests and nature areas. Trees along unpaved roads, with a few exceptions, will also not be sprayed. The municipality hopes this will allow the oak processionary caterpillar’s natural predators to develop.

Each year, fewer trees are treated because pest pressure decreases annually and monitoring with pheromone traps provides an accurate picture of future pest pressure. As a result, areas that are not located along major cycling routes and are situated in rural areas are increasingly left untreated. Thanks to the implementation of a less intensive mowing policy in recent years, roadside verges have more space for the development of natural enemies such as parasitic wasps. These can naturally control the damage caused by caterpillars.

Learn more

More information on oak processionary caterpillars can be found on our website.
Do you have any questions? If so, please contact us by calling 040 - 263 16 31.

The trees to be treated will be viewable on dommelvallei.kaartviewer.nl