"Pesticides harm more and different organisms than previously thought: Fungicides destroy fungi that benefit plants, weed killers starve insects, and insecticides also harm amphibians, for example.
Pesticides affect the entire food chain and are a cause of the massive loss of biodiversity observed worldwide.
Researchers from China, Italy, France, Denmark, the United Kingdom, and Germany have just published this finding in "Nature Communications."
For their study on pesticides and biodiversity, the authors evaluated more than 1,700 studies, considering only those that examined realistic pesticide doses—the amounts that farmers actually apply to their fields. The study examined the effects of 471 active ingredients in insecticides, fungicides, and herbicides on 830 different species of animals, plants, and microorganisms.
For biodiversity in fields and plantations, it therefore makes no difference whether they are treated with modern pesticides or with those designed to specifically combat individual organisms.
The newly developed active ingredients are no more gentle than the older ones.
For approval studies, the pesticides are only tested on individual model organisms, such as zebrafish, crustaceans, rats, algae, earthworms, or honeybees. How the substances affect entire ecosystems is not a criterion for approval. Therefore, the study authors write, less and more efficient use of pesticides must be encouraged.
One of the study authors is biologist Christoph Scherber, Deputy Director General at the Leibniz Institute for the Analysis of Biodiversity Change in Bonn. He conducts research projects on biodiversity together with farmers. He believes it makes little sense to tighten approval regulations or simply prohibit farmers from using pesticides.
Instead, he advocates a rethink of the agricultural system, he says: "I believe it's a mistake to rely so heavily on monocultures," because they can only be maintained with great effort. The solution, in his view, is diversification: flower strips, mixed cropping, crop rotation. It "almost doesn't matter what you do, as long as you move away from monoculture, which is always dependent on pesticides." That doesn't necessarily mean organic farming.
Farmers often fear that yields will decrease if they divert some of their fields to flower strips. "But there are areas almost everywhere," says Scherber, "that are difficult to cultivate, where the soil doesn't produce any crops, where water is stagnant, or where it's shady." Not cultivating such areas, he says, benefits biodiversity and also helps stabilize yields.
Mixed cropping can also contribute to less pesticide use and healthy fields, according to the results of Scherber's research. In an earlier study, for example, a mixed crop of 90 percent durum wheat and 10 percent field beans worked well: In a field where wheat, field beans (Vicia faba), and flax grew, the number of arthropods, which include insects, increased. The yield did not decrease. "The moment more than one species is cultivated, the root space improves, yield stability increases, and water retention increases," says Scherber.
However, the appropriate machinery for harvesting mixed crops or sorting the crops is often lacking. This is a task for agricultural machinery manufacturers, says Scherber. "It's a purely mechanical question." If a field is used to grow animal feed or plants for bioenergy production, there is no need to sort the harvest at all.” [1]
1. Keine Angst vor Natur: Wie weniger Pestizide machbar sind. Frankfurter Allgemeine Zeitung; Frankfurt. 19 Feb 2025: N1. FRAUKE ZBIKOWSKI
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