It all started nearly a century ago. The Stolk Brothers' journey in horticulture began in 1925 when Pieter Stolk's great-grandfather bought land in Bergschenhoek and started growing lettuce. Over the years, the family's dedication to innovation and sustainable practices led them through various crops—from lettuce to tomatoes, and eventually to their current specialty: anthuriums.
For Pieter Stolk, the shift to biological crop protection was both a necessity and a calling. "In the early '90s, my father and uncle started working with Koppert, driven by firsthand experience of the impact of chemical pesticides. My father developed severe eczema from handling chemical sprays, and it became clear that we needed a better, healthier alternative." That's when they turned to Koppert's biological solutions.
At the time, biological pest control was seen as unconventional and was often met with skepticism. "People thought we were crazy, calling us the 'guys with bugs,'" Pieter recalls. "But fast forward 30 years, and now you can't imagine horticulture without biological pest control."
The connection between Stolk Brothers and Koppert runs deep. "Our families have known each other for years. That foundation of trust made it easy to work together," Pieter explains. "Koppert has grown tremendously, but it remains a family business at heart—focused on quality, innovation, and close relationships."
Despite Koppert's expansion, Stolk Brothers continues to feel the company's personal touch. "Fifteen, twenty years ago, you could just call someone at Koppert and get a sample to try out. Things have become more structured, but the essence of the company—the accessibility, the shared commitment to sustainable growing—remains."
Predatory mites: the backbone of a sustainable strategy
For Stolk Brothers, predatory mites form the foundation of their biological crop protection strategy. "We started with predatory mites and have since incorporated bio fungicides and other biocontrol agents. But at the core, predatory mites are our go-to solution," says Pieter.
Initially, biological control was used reactively—similar to chemical treatments—only applying predatory mites when pests were spotted. "Over time, we realized that's not how biological control works best. Now, we take a proactive approach, maintaining a strong population of predatory mites throughout the entire crop cycle." This shift has led to more resilient plants and a more sustainable growing process.
The road to chemical-free horticulture
Looking ahead, Pieter sees a future where horticulture is entirely free of chemical pesticides. "It's achievable, but we need full commitment—not just from growers, but also from policymakers in The Hague and Brussels. We need clear regulations and support, not shifting policies that make long-term planning impossible."
The transition to biological control hasn't always been smooth. "We've tried all kinds of methods—some worked, some didn't. I remember one experiment with a garlic-based product. We applied it in the evening, and by morning, the entire greenhouse smelled like a giant shawarma stand. Our workers were not impressed," Pieter laughs. "That was a lesson in balance—innovation is great, but practicality matters too."
A future built on collaboration
One of the key reasons Stolk Brothers continues to partner with Koppert is the company's reliability and dedication to growers. "Koppert is more than just a supplier; they're a partner in our journey. Their consultants help us stay ahead of potential issues, not just reacting to today's challenges but planning for the future."
As horticulture evolves, Pieter believes that consumer education will be crucial. "People still associate clean-looking plants with quality, but they don't realize that a chemical-free plant is actually the healthier choice. If a predatory mite leaves behind some residue, it's proof that biological control is working—but consumers don't always see it that way yet."
Despite the challenges, Pieter remains optimistic. "Every year, we improve. Every year, we refine our methods. And with partners like Koppert, we know we're on the right path to a more sustainable, chemical-free future."
For more information:
Koppert
info@koppert.com
www.koppert.com