News
Twenty horticulture companies testing biodiversity strips next to their greenhouses
At the end of 2024, we started working with twenty horticulture companies spread across the Netherlands to establish 250 m² biodiversity strips next to their greenhouses. In these strips, we are testing two specially composed flower mixtures, consisting of annual, biennial, and perennial plants. Our goal is to enhance biodiversity and attract natural enemies of greenhouse pests. At the same time, we are investigating how these strips influence the influx of harmful pests. The challenge is to strike the right balance: attracting as many beneficial insects as possible without increasing the risk of pests.
Impact of biodiversity on pest control
We are conducting this project with a wide range of crops, including bell pepper, potted plants, tomato, chrysanthemum, gerbera, cymbidium, lily, and strawberry. To create a favorable environment for natural enemies, we use a variety of plants and shrubs. These provide shelter, nectar, alternative prey, and pollen, enabling a diverse population of beneficial insects to settle and be supported. Each of the companies has established a biodiversity strip, but also a 250 m² control plot with short-mown grass. By comparing these two situations, researchers can accurately measure the impact of the biodiversity strips. We are also looking at the role of green corridors and the influence of surrounding vegetation on the effectiveness of the strips.
Based on literature and previous research, two flower mixtures were developed. The first mixture focuses on attracting predators such as lacewings, hoverflies, and ladybugs, which help control aphids. In the second mixture, plants that are attractive to thrips have been deliberately omitted to minimize the risk of this pest. Twelve of our companies have sown the first mixture, eight the second. We are looking very specifically at what works in practice. Which plants attract beneficial insects without simultaneously introducing additional risks?
In addition, four types of young trees have been planted at the test locations that attract specific species of aphids. These aphids do not pose a threat to the greenhouse crops but serve as a food source for natural enemies and thus contribute to integrated pest management.
The biodiversity strips were successfully established at the end of 2024. The first seedlings are now visible, and we expect most plants to emerge in May and bloom in June. In the coming years, our research will focus on the development of biodiversity and the effects on pest control. Researchers from WUR will visit regularly in 2025 and 2026 to monitor the biodiversity strips and collect data on the presence of beneficial insects and potential pests.
From knowledge to greenhouse
Throughout the study, we compare the effects of both mixtures on natural enemies and pest control. We not only examine the increase in beneficial insects but also look at possible risks, such as increased pest influx or virus transmission. At the same time, we are developing innovative methods to harvest natural enemies from the biodiversity strips and deploy them in the greenhouse. Ultimately, this research should help growers to choose the right biodiversity composition, tailored to the crop and specific pest pressure. For example, if we experience significant thrips issues, we can avoid certain plants, while in the case of aphid problems, we can choose species that attract a high number of natural enemies.
We are looking very specifically at what works in practice. Which plants attract beneficial insects without simultaneously introducing additional risks?
Collaboration and financing
This project is a collaboration between Glastuinbouw Nederland, Wageningen University & Research, and Leiden University. Funding is provided by the Ministry of LVVN, Stichting KijK, Innovatiefonds Hagelunie, the province of South Holland (via Greenport West-Holland), the municipality of Westland, Glastuinbouwpact Bommelerwaard & Tielerwaard, and the Hoogheemraadschap Delfland. In addition, Biobest, ECW Energy, and the Federation of Fruit Vegetable Organizations are contributing in kind. Through this collaboration, we as growers and researchers are taking a joint step toward a more sustainable and resilient cultivation system.