One of the affected areas is a forest path along the adventure trail on the Hardtberg. "A specialist company will remove the nest as quickly as possible," says Andrea Schulte from the press office. The second nest is located in a private forest on the Venusberg near the Waldau car park. The city foresters have put up signs at the closures to draw attention to the health hazard posed by the pest. From May until September, the caterpillar poses serious danger.

"From the third shedding, it is covered with over 600,000 stinging bristles," explains Sabine Krömer-Butz from the German Forest Protection Association. "The microscopic bristles have little barbs and break easily. The nettle poison it contains is dangerous for humans and animals." If touched, it can cause allergic reactions. Itching is often followed by skin inflammation. This can range from local skin rashes to hives all over the body, bronchitis, asthma, dizziness, fever and, in the worst case, allergic shock. Irritations of the mucous membranes of the eyes and respiratory tract are frequent.

Throughout the entire year, there is a toxic risk but in a lesser form. The stinging bristles are stripped off during shedding and can be spread by the wind. Old nests are also dangerous all year round.

Forest owners have another reason to be hostile to the oak processional caterpillars. As the name suggests, the caterpillars prefer to feed on young oak leaves. From the end of May onwards they go on their typical processional migration to build nests on trees. The feeding damage becomes quickly visible. "As a rule, the deciduous trees are able to compensate for one-off feeding," explains Krömer-Butz. If there is an accumulation of years of feeding, combined with drought, the oaks can die.

Over the past 20 years, the population density of oak processionary caterpillars has increased significantly. On the basis of the data, Krömer-Butz notes that they have been spreading mainly since the extreme summers. "Public areas such as kindergartens, schools or parks are most frequently affected.

Residents and walkers in affected forest areas, visitors to recreational facilities with oak trees and firewood buyers are also among the risk groups," she says, adding: "In Bonn this year, nests of the oak processionary caterpillar were reported at around 30 locations in public spaces outside the forest," Schulte reports. "The tree inspectors of the Amt für Stadtgrün (City Parks Department) immediately check the reports and, if the suspicion is confirmed, get a specialist company to remove the nests.”

When asked about eradicating the caterpillars, Krömer-Butz explains: "Because of the danger to humans, dogs and other animals, Eco-pesticide are used in most cases. The caterpillars could also be selectively extracted by vacuum". Further defensive measures, especially for individual trees in urban areas, are being worked on. “If walkers discover a nest, they should immediately move away from the tree," she advises. After spending time in infested areas, they should shower and change their clothes as soon as possible.

It is important to report the discovery of a nest of oak processionary caterpillars quickly. The contact person is the Amt für Stadtgrün under the phone number 02 28/77 44 99 or by e-mail to info-stadtgruenbonnde. If an infestation is suspected on their own property, owners should contact a tree care service or pest controller.

Orig. text: ga.de

Translation: ck