Flower strips control pests just as well as insecticides

Biodiversity is in a poor state in many agricultural landscapes. Intensive cultivation methods, such as the massive use of pesticides, are to blame. The need for sustainable plant protection is therefore great. A new study with LIB involvement is investigating whether flower strips on sugar beet fields can replace insecticides - with surprising results.

Insecticides often not only control pests such as aphids, but also beneficial insects such as ladybirds and bees. They also harbour health risks. For this reason, the European Union (EU) has banned many insecticides such as neonicotinoids, which were previously used in sugar beet cultivation. The search for biological alternatives is in full swing. In various projects, the LIB is researching whether flower strips that attract beneficial insects could be an alternative to chemical pesticides.

Field beans are particularly effective

This is also the case in the "FlowerBeet" project, which the LIB is carrying out together with the Institute for Sugar Beet Research. Over the past few years, researchers have created flower strips around six metres wide in the middle of sugar beet fields at ten locations across Germany and investigated the impact this has on the number of pests and beneficial insects as well as on yield. They varied the composition of the flowering strips experimentally, using many different plant families, such as legumes, composite and umbelliferous plants.

The researchers recently presented the results in a study in the Journal of Applied Sciences: all flower mixtures effectively reduced the aphid populations compared to untreated control areas up to at least ten metres into the field - with similar sugar yields. Some mixtures were at least as effective as insecticides, whereby mixtures with legumes were particularly effective against aphids, especially the field bean. "This is an astonishing result that we did not expect to see so clearly," reports LIB researcher Ingo Glock. "We suspect that legumes attract certain predators (predators and parasitoids) early in the season, which directly attack the aphids when they fly in. On the other hand, the field bean itself appears to be even more attractive to aphids, especially the black bean aphid, than the sugar beet." Biodiversity was also significantly higher in the areas around the flower strips compared to the control areas.

Further research needed

The research conducted as part of the "FlowerBeet" project is an important step towards more sustainable cultivation methods. The results show that flower strips can be an effective method of pest control in agriculture, with sugar beet cultivation being just one of many possible examples.

However, the participating farmers also had higher financial costs as a result of the flower strips, as they had to buy seeds and maintain the flower strips. In addition, their sugar beet cultivation area was reduced. "Without subsidies, this would not yet be profitable as things stand," says Glock. However, economic losses could be reduced if mixed crops of legumes and other crops were planted in alternating strips.

Further research is needed to investigate the possible effects of the flower strips on the subsequent crops and to optimise the composition of the plant species in such a way that both pest control is as successful as possible and the benefits for biodiversity are as great as possible.

Publication

Glock, I., Sodtke, K., Wieters, B., Witt, F. K., Lubjuhn, J., Scherber, C. 2026. "Insecticide-level pest control provided by in-field flower strips". Journal of Applied Sciences, 63, 4 (April 2026). https://doi.org/10.1111/1365-2664.70378

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