Stock Photo - 11 July 2023, North Rhine-Westphalia, Saerbeck: Ole Theisinger, a research assistant at Wald und Holz NRW, aims his paintball rifle at a web of oak processionary moth caterpillars. He uses the gun to fire small balls at air pressure at the oaks in an avenue. The bullets, which cost 2.50 euros each, contain a pheromone to attract the oak processionary moths. In a project, eight spheres per oak tree are now being shot at different heights onto the trunks of the 70 trees along the avenue. This is intended to confuse the caterpillars of the oak processionary moth in order to prevent them from spreading. After four weeks, the procedure must be repeated. Photo: Christoph Reichwein/dpa. - Saerbeck/North Rhine-Westphalia/Germany