The decline in insect populations is a global challenge (Cardoso et al., 2020), with chemically synthesized plant protection products (csPPP) considered to be a major cause (Sánchez-Bayo & Wyckhuys, 2019; Wagner et al., 2021). Although 283 pesticide active substances are authorized in Germany and an average of 2.8 kg are applied per hectare per year (Umweltbundesamt 2023), there is hardly any data available on the environmental impacts of csPPPs on non-target insects. Initial results show that even insects in nature reserves are contaminated with csPPPs (Brühl et al., 2021) and that pesticides are also found in the environment far away from agricultural land (Brühl et al., 2024). Little is known about the effects of pesticides on terrestrial insect communities and biodiversity.

The aim of the project is to examine the contamination of agricultural land and neighboring landscapes with synthetic chemical pesticides and to investigate their influence on selected insect groups. It is being investigated whether organic farming without the use of pesticides has less negative or even positive effects on biodiversity. Environmentally friendly alternatives to conventional pesticides are also being tested. The results obtained will serve as a basis for further sub-projects of the biodiversity cluster and will be merged with the overall biodiversity data.

10 pairs of landscapes (1 km² area each) are to be analyzed comparatively, with the focus on arable land with wheat. One of the landscapes should have the highest possible proportion of organically farmed wheat fields, while the corresponding comparison landscape should be predominantly conventionally farmed. Comprehensive monitoring of 98 currently used synthetic chemical pesticides (insecticides, fungicides, herbicides) in soil and vegetation samples will be carried out on all areas. The data forms the basis for identifying potential deficiencies in the risk assessment of plant protection products.

In parallel, detailed biodiversity studies are being carried out on butterflies, grasshoppers and plant bugs, which react very sensitively to insecticides and thus reveal the effects of plant protection products on biodiversity.