Biocontrol mechanisms of Paecilomyces spp. for the management of fungal plant diseases: a review.

Paecilomyces is a ubiquitous cosmopolitan fungus. Recent reports have demonstrated that Paecilomyces strains are efficient biocontrol agents for the management of plant pathogens in a variety of crops and plant tissues. This review covers the biocontrol methods based on the use of Paecilomyces spp. for the management of pathogenic fungi and oomycetes. Paecilomyces spp. showed high efficacies for the control of plant pathogens in various hosts under greenhouse conditions and in fields, demonstrating their actual applicability. The efficacies were especially high for the management of wilts and damping-offs. Paecilomyces spp. showed a variety of antifungal mechanisms, including the production of antifungal non-volatile compounds, VOCs, and hydrolytic enzymes, competition for space and nutrients, and induction of disease resistance. Application of Paecilomyces spores resulted in higher efficacies compared to the application of the cell-free culture filtrate. Despite the interesting biocontrol properties of Paecilomyces, some Paecilomyces spp. can cause keratitis in humans, synthesize the hazardous mycotoxin patulin, and be a cause of fruit juice spoilage. To date, only the P. variotii extract ZhiNengCong has been commercialized for agricultural purposes. Collectively, further research regarding toxicity and storage conditions is necessary to confirm the potential commercialization of the strains. Studies regarding the key metabolites and genes involved in Paecilomyces antifungal activity are necessary to understand and optimize the antifungal properties of this emerging biocontrol agent. © 2025 Society of Chemical Industry.