At the end of 2024, a group of horticulture businesses across the Netherlands established a 250-square-meter biodiversity strip next to their greenhouse. In 2025, researchers tracked how these strips developed more than six monitoring rounds. The findings were compared with equally sized areas of short-mown grass. The project’s central question was whether flowers and other plants around the greenhouse attract more beneficial insects, without causing extra influxes of pests.
More Pollinators and Natural Enemies
“The first results show that biodiversity strips contain more bees, bumblebees, hoverflies, and butterflies than grass,” says WUR researcher Kyra Vervoorn. “On average, we recorded more than 20 times as many bees and bumblebees there. Natural enemies of glasshouse pests were also present in higher numbers, including Orius (a small predatory bug) and lacewings. Ladybirds were observed three to four times more often.”
That does not automatically mean that more natural enemies are also present inside the greenhouse itself. That link has not yet been studied at this stage. The results do show that the strips function as a habitat for beneficial insects in the immediate surroundings of the greenhouse.
Aphids as a Food Source, Not a Threat
In total, the researchers identified 23 aphid species. Many of these appear to be associated with specific plants in the strips or in the surrounding vegetation. Most species are specialists or depend on plants outside the greenhouse. “Most of the aphids we find, therefore, do not pose a risk to the crop,” says Vervoorn. “They may actually serve as a food source for natural enemies.”
Virus study: TSWV Also Found in Control Areas
In addition to insect numbers, the researchers are also examining possible virus transmission. During the summer months, thrips numbers increased, a pattern consistent with earlier observations. Thrips from flower samples were tested for tomato spotted wilt virus (TSWV) using PCR, a method that can detect viral genetic material.
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TSWV fragments were found in thrips at 13 of the 20 businesses, spread across all regions. “This means that viral genetic material is present, but it does not confirm that thrips are actually able to transmit the virus,” says Vervoorn. “What is more, TSWV was also found in plants in the control areas. On the basis of these results, the virus therefore cannot be directly linked to the biodiversity strips.”
For additional information on the effectiveness of biodiversity trips in attracting beneficial insects, including a follow-up 2026 study tracking results after an additional year of monitoring, please read the original article on the Wageningen University & Research website.
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How Biodiversity Strips Help to Attract More Beneficial Insects
The Netherlands-based Wageningen University & Research (WUR) combines fundamental and applied knowledge in order to contribute to resolving important questions in the domain of healthy food and living environments. See all author stories here.