Achieving world food production for the growing population is a key target in the 2030 Agenda of the United Nations. Yet this goal hinges on controlling crop losses caused by plant diseases. To accomplish this, sustainable and safe new methods are essential. Biocontrol, or biological control, uses harmless microorganisms to prevent crop disease. It sounds promising.
The plague of phytopathogens
Phytopathogens are microorganisms that attack plants. They can affect roots, leaves, stems, and even fruits, sometimes leading to plant death. The economic impact on the agri-food sector is immense: the FAO estimates about 220 billion dollars (roughly 200 billion euros) are lost each year due to crop diseases.
Additionally, climate change fuels the emergence, increased severity, and spread of bacterial and fungal pathogens, underscoring the need for effective control methods.
Traditionally, such controls relied on chemical compounds and antimicrobials. However, there are many reasons to limit their use.
First, rising antimicrobial resistance calls for an approach that considers human, animal, environmental health in a single framework, with agriculture playing a central role. A broader One Health perspective highlights the interconnectedness of health across sectors.
Moreover, residues from these chemicals can pose risks to human and animal health and to ecosystems. Their use is regulated in the European Union, with an ongoing review of authorized products. The shift toward organic farming also restricts many chemical antimicrobials.
Fight to the death between germs
Biological control agents (BCAs) are the microorganisms used to manage plant diseases. They are chosen from the same environments where they will be applied, ensuring adaptation and permanence after release.
Care is taken to ensure their release does not create ecological problems or disrupt beneficial microorganisms in the ecosystem. BCAs are selected to target specific pathogens while sparing the normal microbiota of the environment.
Understanding biological control can be imagined as a miniature war: pathogens and BCAs compete to colonize the plant. If the pathogen wins, disease occurs; if the BCA wins, the plant stays healthy.
How does biological control work?
The mechanisms by which BCAs prevent plant diseases are diverse. Often they block pathogen development or relocate it away from the plant. BCAs are highly adaptable, grow quickly, and occupy niches that prevent harmful microbes from thriving on the plant.
Another key aspect is that many BCAs produce antimicrobial compounds that kill or inhibit the attacker. This is an ancient microbial strategy used to compete for space and resources, repurposed here to benefit crops.
In many cases, the presence of BCAs also boosts the plant’s defenses, helping the crop respond more rapidly if a pathogen appears.
A mushroom choking like a boa constrictor
Often, a single agent uses multiple strategies. Trichoderma is one of the leading BCAs, notable for activity against a broad range of pathogens.
This fungus is versatile and offers unique benefits for disease control. It grows rapidly in diverse environments, uses various nutrients, and many strains produce antimicrobials as well as compounds that enhance plant defenses.
Its most remarkable feature is hyperparasitism. Trichoderma can directly attack other pathogenic fungi, using its hyphae to trap and degrade the invaders with specialized enzymes.
Biopesticides come (shy)
Today there are commercial formulations containing bacteria and fungi designed to biologically control plant diseases. These products are called biopesticides, but they still represent only about 5% of the global pesticide market. Much work remains to develop effective products that pass all regulatory hurdles.
The first step is to create a stable formula that maintains BCAs in their active state for as long as possible while maximizing their antagonistic effect when applied.
After development and patenting, the product must be registered for agricultural use, ensuring compliance with health and environmental safety criteria. The regulatory requirements are strict, meaning many promising BCAs never reach field use.
The use of beneficial microorganisms in agriculture to combat pathogens highlights the positive potential of microbiology. While progress continues, this approach could become a sustainable and effective alternative to chemical pesticides in the future.
This article reflects ongoing research in plant protection and the evolving landscape of sustainable agriculture, emphasizing the role of BCAs and biopesticides in reducing chemical inputs.
No external sources are cited directly in this text; the information reflects widely discussed findings in the field of plant pathology and biocontrol strategies.
— A researcher notes the importance of responsible development in this area and the potential for BCAs to contribute to safer, more sustainable farming practices.
The goal remains clear: advance biologically based solutions that protect crops while safeguarding health and the environment.