A dash of daisies and a touch of yarrow could be a farmer’s best allies. New research reveals that even modest strips of wildflowers can drastically reduce pest populations by empowering nature’s own army of predators.
Key Points at a Glance
- Two-species flower strips increase pest-eating insects by 70%
- Each additional flower species adds 4.1% more natural enemies
- Native, perennial species like yarrow and ox-eye daisy perform best
- Study supports EU policy to cut pesticide use by 50% by 2030
- Farmers face hurdles in subsidy access for planting such strips
They may seem like simple streaks of color at the edge of a wheat or barley field, but flower strips — carefully planted rows of wild blooms like ox-eye daisies, bellis, and yarrow — are proving to be powerful tools in the battle against crop pests. A new meta-analysis from the University of Copenhagen finds that planting just two species of flowers along field margins can increase the number of pest-eating insects by a striking 70 percent. The more flower species included, the greater the ecological army that assembles to protect crops.
The study, led by PhD researcher Nika Jachowicz and Associate Professor Lene Sigsgaard from the Department of Plant and Environmental Sciences, is the first to focus exclusively on flower strips in annual crop fields—areas typically more disturbed and less hospitable to biodiversity than perennial systems. The findings add strong scientific weight to efforts aimed at reducing pesticide dependence in agriculture, aligning with the European Union’s goal of halving pesticide use by 2030.
The concept is simple but impactful: a diverse mix of blooming plants sustains predatory insects—like ladybirds, hoverflies, soldier beetles, and green lacewings—that feed on pests such as aphids, thrips, and spider mites. Importantly, these flowers don’t just look pretty; they feed and shelter beneficial insects through the growing season. “Diversity pays off,” says Sigsgaard. “Two species are good, but with each additional species, you gain even more natural pest control.”
In practical terms, each added species boosts natural enemy populations by around 4.1 percent. That means farmers can see meaningful ecological benefits from relatively small investments in flower diversity. These beneficial insects aren’t just passive guests—they’re active hunters, helping reduce reliance on synthetic chemicals.
Why does diversity matter so much? The answer lies in flowering schedules and insect preferences. Different flower species bloom at different times, ensuring a steady food supply across the season. Moreover, specific insects are attracted to specific floral traits—so a wider menu of nectar and pollen options supports a broader cast of predator and pollinator species.
Certain flower types stand out for their effectiveness. Open flowers like those of yarrow, ox-eye daisy, bellis, and umbellifers make pollen and nectar easily accessible to predatory insects, parasitic wasps, and solitary bees. “These are the kinds of flowers that really do the work,” Jachowicz explains.
But success isn’t just about species count. Native perennial plants offer unique advantages: they’re well-adapted to local insect fauna and can survive across seasons, providing shelter for overwintering insects. This means next spring’s natural enemies are already in place and ready to defend the crops. According to Sigsgaard, “Perennial flower strips can last for years and help build resilient insect populations—enhancing both biodiversity and yield.”
However, the researchers caution that widespread adoption still faces policy barriers. Despite long-standing EU support for flower strips, farmers report that applying for subsidies is complex and sometimes counterintuitive. “Rules around when to sow and mow are often too rigid,” says Jachowicz, urging authorities to simplify access and align procedures with ecological objectives.
Flower strips alone won’t eliminate the need for other pest control strategies, but their potential is significant—especially when combined with crop rotation and biological controls. They are a simple, visible, and effective way to restore balance between pests and their predators. As agriculture moves toward sustainability, it’s these quiet strips of wild beauty that may prove to be the most powerful agents of change.
Source: University of Copenhagen
