Biocontrol Strategies Against Powdery Mildew Fungi

Powdery mildews are obligate fungal pathogens that affect a broad range of crops worldwide, causing significant yield losses and compromising food security. Traditional reliance on synthetic fungicides has prompted concerns over environmental impact, resistance development and human health. In response, biocontrol strategies have emerged as sustainable alternatives. These encompass the use of microbial antagonists, such as epiphytic and endophytic yeasts or filamentous fungi, which deploy antibiosis, competition for space and nutrients, and direct mycoparasitism to suppress mildew growth. Plant-derived elicitors and natural polymers can induce host defences through pathways such as systemic acquired resistance, leading to callose deposition, reactive oxygen species production and accumulation of phenolic compounds. Advances in genomics and imaging have elucidated effector repertoires and interaction dynamics of mycoparasites, enabling rational development of biocontrol strains. Integrating these biological agents with cultural practices and minimal fungicide inputs offers a holistic approach that reduces chemical dependency, mitigates resistance and aligns with global imperatives for environmentally benign crop protection.

Research from Nature Portfolio

One study investigated the foliar application of a giant knotweed extract as a natural elicitor in courgette genotypes. Treatment triggered salicylic acid-dependent defence responses, including rapid callose papilla formation and hydrogen peroxide accumulation, leading to a marked reduction in powdery mildew severity on both intermediate-resistance and susceptible cultivars. Enhanced levels of p-coumaric and caffeic acids were detected, demonstrating that induction of the salicylic acid pathway by plant-derived compounds can effectively prime host defences and improve disease control without synthetic fungicides.

Biocontrol Strategies Against Powdery Mildew Fungi publication trend

The graph below shows the total number of articles in biocontrol strategies against powdery mildew fungi across all publications each year (not limited to Nature Index journals).

Technical terms

Biocontrol agent: A living organism employed to suppress a plant pathogen through direct or indirect antagonistic mechanisms.

Mycoparasitism: A mode of antagonism in which one fungus parasitises and derives nutrients from another fungal species.

Elicitor: A compound, often of biological origin, that stimulates host defence pathways against pathogens.

Systemic Acquired Resistance (SAR): A plant-wide immunological state induced by local stress or elicitor application, conferring broad-spectrum disease resistance.

Effector gene: A pathogen- or antagonist-encoded gene that modulates host or opponent cell processes during interaction.

References

1. Reynoutria sachalinensis extract elicits SA-dependent defense responses in courgette genotypes against powdery mildew caused by Podosphaera xanthii. Scientific Reports (2020).
2. Potential of Chitosan for the Control of Powdery Mildew (Leveillula taurica (Lév.) Arnaud) in a Jalapeño Pepper (Capsicum annuum L.) Cultivar. Plants (2024).
3. Deciphering the genome of Simplicillium aogashimaense to understand its mechanisms against the wheat powdery mildew fungus Blumeria graminis f. sp. tritici. Phytopathology Research (2022).
4. Biocontrol action of Trichothecium roseum against the wheat powdery mildew fungus Blumeria graminis f. sp. tritici. Frontiers in Sustainable Food Systems (2022).