Yellow alert: bark beetle invasion threatens Traunstein forests!

Yellow alert: bark beetle invasion threatens Traunstein forests!

Things are currently looking bleak for the trees in the picturesque districts of Traunstein and Berchtesgadener Land. There is a threat of a massive spread of the bark beetle this summer of 2025. Loud Chiemgau24 The Traunstein Office for Food, Agriculture and Forestry (AELF) has already declared the warning level “yellow”.

High temperatures and persistent drought in spring have encouraged bark beetle activity. At the moment the beetles are increasingly swarming out to look for new breeding space. This is a worrying sign because the signs of an infestation are clearly visible: small holes on the tree trunk and fine, dark brown drill dust, which can often be found in spider webs or in the moss at the base of the tree, are clear indicators. If you discover such traces, you should not hesitate, because time is of the essence!

Bark beetle infestation: what to do?

Forest owners should immediately cut down infected trees and make sure to remove them at least 500 meters from the forest. The potential dangers are compounded by the swarming of first-generation young beetles, which are not supposed to be active at this time of year. The beetles burrow under the bark of spruce trees and specifically look for breeding space. In addition, the snow last autumn 2024 also caused a lot of breeding material in our forests - an acute risk of a mass infestation seems real.

Record numbers of bark beetles were even counted in traps, more than ever before this time of year. It is urgently necessary to check the spruce stands for new infestations every two weeks and to take active action against the beetles, because areas that are already infested, sunny forest areas, forest edges and stands that have recently been opened by clear-cutting are particularly at risk.

The bark beetle in detail

But what exactly are these beetles that are causing us so much trouble? The book printer, one of the most common species, is a brown beetle about 4-5 mm long. It has no visible head under the large pronotum and prefers Norway spruce as a food source. But larch, Douglas fir, black pine and silver fir are also on his menu. Interestingly, the book printer leaves its winter quarters as soon as temperatures rise above 16.5 degrees Celsius and the days become longer. And this is where the vicious circle begins: After successfully penetrating the tree, the beetles produce attractants that attract other members of their species.

Again My beautiful garden explains, the males drill their own chambers in order to mate with the females. These then attack their mother tunnels along the trunk and lay their eggs in niches. The larvae hatch after about ten days and continue to bore into the wood. The entire development from the egg to the swarming of the young beetles can take between six and ten weeks under ideal conditions.

In order to meet this challenge, the AELF district foresters are available free of charge to answer questions about the infestation and how to combat it. It's high time to protect our region's forests and take active action against bark beetles!