"Blind" use of the insecticide cypermethrin in the forest
The insecticide cypermethrin is sprayed in large quantities on felled tree trunks in the Swiss forest. It is intended to keep the bark beetle away. However, the effect of cypermethrin on forest organisms was never studied before it was approved. Recently, the parliament approved larger wood storage facilities in the forest. This provokes a correspondingly higher use of the toxin.
The Forest Act prohibits the use of pesticides, but allows exceptions. These became the rule: around 700 kilograms of highly toxic insecticides were sprayed on spruce logs stored in the forest in 2018, reports a media release from Doctors for Environmental Protection (AefU). This is because felled tree trunks with bark, for example, attract the bark beetle. As a precaution, they are treated with insecticides. Now the use of poisons is likely to increase: Recently, the parliament approved larger wood storage facilities in the forest. This means even more insecticide. If, on the other hand, the felled wood were debarked or stacked outside the forests, there would be no need for the poison at all.
Cypermethrin: Approval without testing in the forest
Today, the highly toxic insecticide cypermethrin is primarily used in timber stockpiles in Swiss forests. It was approved for use in the forest without the approval authority having clarified how the poison acts in the sensitive forest ecosystem. The responsible Federal Office for Agriculture FOAG confirmed this to the AefU: "Forest organisms, i.e. forest-typical species" were "not specifically tested". In other words, the FOAG granted the approval "blindly". The effects of cypermethrin on forest organisms are still largely unknown.
A few nanograms do harm
The toxin can be detected for a long time on the bark of treated logs. This is shown by an analysis commissioned by the AefU. 20 micrograms of cypermethrin per kilogram of outer bark layer were still detected by the Cantonal Laboratory of Zurich around four months after the poison was applied to a wood store in the Sernftal (GL). However, because hand spraying is not carried out uniformly, the concentration of poison on the bark can fluctuate massively.
Bees, bumblebees and earthworms in danger
As a broad-spectrum insecticide, cypermethrin not only acts against the bark beetle: bees, bumblebees and earthworms that come into contact with the sprayed bark surface are potentially at risk. Heinz Köhler, professor at the Institute of Ecology and Evolution at the University of Tübingen, says: "Even an intake of a few nanograms per animal leads to neuronal damage and behavioral deficits in bees and bumblebees." Heinz Köhler even considers the risk to earthworms to be unacceptable. There are no studies on millipedes. And the forest ants? Some ant species would even be "actively combated" with cypermethrin, so it massively harms them. The Swiss Bee Health Service writes: "Ants as well as bees are hymenopterans: What kills ants is also deadly for bees", which is of course equally true the other way round.
Parliament provokes insecticide use
Despite this, the parliament recently approved larger roundwood stores in the forest - without the requirement that the logs be debarked beforehand. Parliament is thus provoking the use of even more insecticides in the forest and thus in one of our most important drinking water resources.
This is the wrong way to go. The AefU demands the consistent enforcement of the pesticide ban in the forest. Fallen logs should be immediately removed from the forest or consistently debarked, which is necessary anyway before processing. The timber industry must make this contribution to the protection of forests and drinking water.
