In the War on Pests, Farmers Turn to Nature’s Own Weapons

By Lewis Wachira

In many African societies, there’s an old saying: “Set a thief to catch a thief.” This summary of well-worn sagacity finds a fascinating parallel in modern horticulture. As consumers become more aware of what goes into producing their food, the clamor for sustainable, health-conscious agricultural practices has only grown louder. With fewer pest control options available, the horticultural industry is turning to natural solutions to combat an increasing number of stubborn pests.

A Natural Solution from Within Nature

Just as the adage suggests using a thief’s knowledge to catch them, scientists are harnessing the intricate mechanisms of microbes to outsmart crop pests. From the fertile open fields of Africa to greenhouses around the world, these tiny organisms are proving that sometimes, the best solutions come from within nature itself.

While biological controls are somewhat considered a novel innovation, their use has deep roots in agrarian societies around the world. For example, in Brazil, sugarcane farmers have successfully used Cotesia flavipes, a parasitoid wasp, to control the sugarcane borer, a pest responsible for devastating crop losses. This practice has been in place since the 1970s and is credited with saving the industry millions of dollars annually.

“The microbial fungi we offer to farmers are nature’s own pest control mechanisms,” says Dr. Vitalis Wekesa, Head of Production at Bioline Agrosciences. “They’ve evolved to target specific pests without harming beneficial insects or the environment.”

The Science Behind Precision Pest Management

Bioline’s range of microbial products — Beauvitech, Lecatech, Trichotech, Mytech, and Rhizatech— offer a comprehensive suite of solutions that are environmentally safe, compatible with Integrated Pest Management (IPM) programs, and beneficial for long-term plant and soil health.

In Beauvitech, Beauveria bassiana spores attach to the insect’s cuticle, germinate, and penetrate the exoskeleton using a combination of mechanical pressure and enzymatic degradation. Once inside, the fungus multiplies, producing toxins that eventually kill the host. Lecatech’s Lecanicillium lecanii operates similarly but specializes in soft-bodied insects. The fungus not only kills the pest but also produces a white mycelial growth that prevents further pest establishment.

Trichotech, containing Trichoderma asperellum, suppresses soil-borne pathogens and promotes root growth. Mytech, containing Paecilomyces lilacinus manages plant-parasitic nematodes, while Rhizatech, a mycorrhizal fungi product that enhances plant growth by extending root systems and improving nutrient uptake. It contains Arbuscular mycorrhiza fungi, which increase nutrient availability and stimulate plant development.

Integrating with IPM Strategies

These microbial solutions integrate seamlessly into IPM programs. Their specificity in targeting pests while being compatible with beneficial insects makes them ideal for growers aiming to reduce chemical inputs without compromising crop protection.

“Since incorporating Bioline’s microbial products into our weekly crop protection program, we’ve seen a drastic reduction in synthetic chemical pesticide use and a noticeable improvement in overall plant health,” says Dennis Wanjau, Assistant Manager – Production and Technical at DeRuiter E.A Ltd, a prolific flower breeder.

The impact of these microbial products is evident in their ability to provide solutions where traditional methods have failed. In Spain, for instance, the use of Trichoderma species has significantly reduced the incidence of Fusarium wilt in tomato plants, a disease notoriously difficult to manage with chemical fungicides.

The Future of Horticulture

As of September 2024, Kenya is developing a national pesticide residue monitoring framework aimed at reducing the use of highly hazardous pesticides (HHPs). This means regulations will only get tighter, and consumers will increasingly demand residue-free produce. Microbial solutions are poised to play a crucial role in horticulture, addressing current pest management challenges while contributing to long-term soil health and ecosystem balance.

Compared to traditional chemical pesticides, these microbial solutions offer several advantages:

• Specificity: Unlike broad-spectrum chemicals, they target specific pests, minimizing the impact on beneficial insects.
• Resistance Management: Their complex modes of action make it difficult for pests to develop resistance.
• Residue-Free Produce: They break down naturally, leaving no harmful residues on crops.
• Environmental Safety: They have minimal impact on non-target organisms and ecosystems.

“While chemical pesticides might offer quicker knockdown, microbial solutions provide sustainable, long-term pest management,” Dr. Vitalis adds. “They’re particularly valuable in greenhouse environments and for high-value crops where residue concerns are paramount.”

Conclusion

As research continues to unveil the potential of these microscopic allies, the future of horticulture looks not just greener but more innovative, resilient, and attuned to the delicate balance of nature. Dr. Pamela Marrone, a renowned entomologist and founder of Marrone Bio Innovations, predicts, “The biopesticide market is growing rapidly and is expected to reach $10 billion by 2025. Microbial solutions will play a crucial role in sustainable agriculture as we face challenges like climate change and the need for global food security.”