Biodiversity strips established alongside commercial glasshouses in the Netherlands are attracting substantially more pollinators and natural enemies of crop pests than areas of short-mown grass. Initial findings from a nationwide monitoring project led by Wageningen University & Research (WUR), Glastuinbouw Nederland and Universiteit Leiden indicate that these planted strips can provide valuable habitat for beneficial insects in intensive horticultural landscapes.

At the end of 2024, twenty glasshouse horticulture businesses established 250-square-metre biodiversity strips. Researchers monitored the strips over six rounds in 2025 and compared insect populations with those in equally sized grass areas. On average, the strips hosted more than twenty times as many bees and bumblebees, while ladybirds were observed three to four times more often. Other beneficial insects, including hoverflies, butterflies, predatory Orius bugs and lacewings, were also recorded in higher numbers. Researchers identified 23 aphid species, many associated with specific plants and unlikely to threaten greenhouse crops; some may instead provide food for natural enemies. However, the study has not yet established whether greater numbers of beneficial insects around glasshouses translate into higher populations inside them.

The project also investigated potential virus risks. Tomato spotted wilt virus (TSWV) genetic material was detected in thrips at 13 of the 20 businesses, but also in plants in control areas. These findings do not establish that thrips could transmit the virus or that biodiversity strips were responsible for its presence. Monitoring will continue in 2026 to examine relationships between plant species, pests and natural enemies. The longer-term objective is to develop evidence-based guidance for growers on designing biodiversity-friendly glasshouse surroundings while managing crop protection risks.