Harnessing biological control and advanced technologies for sustainable wheat rust management: An integrated approach

Wheat rusts caused by biotrophic fungi of the genus Puccinia continuously threaten global wheat production and food security. The rapid evolution of virulent races, and the limitations of chemical fungicides, including environmental contamination, human health concerns, and resistance development, necessitate a shift towards integrated management strategies. This review explores biocontrol agents (BCAs), including fungal (Trichoderma spp., Cladosporium cladosporioides), bacterial (Bacillus subtilis, Pseudomonas spp.), and actinomycetes (Streptomyces spp.), as foundational components of wheat rusts management. We highlight their modes of action such as mycoparasitism, antibiosis, competition, and the induction of systemic resistance. Additionally, we explore how cutting-edge adjunct technologies can enhance the efficacy and sustainability of BCAs. These include nano-formulations, for targeted antimicrobial actions and plant defense potentiation; plant extracts and antimicrobial peptides as natural defense elicitors; and artificial intelligence (AI) tools, for presymptomatic detection, severity quantification, epidemic forecasting, and early warning systems that enable precise application of BCAs and nano-formulations. While BCAs, nanoformulations, plant extracts and AI-driven tools offer powerful, environmentally benign alternatives capable of significantly reducing reliance on synthetic chemicals, chemical fungicides remain an essential component of current wheat rusts management, particularly during severe epidemics or when rapid knockdown of inoculum is required. A truly integrated and sustainable strategy therefore combines these novel approaches with the judicious, resistance-management-oriented use of effective chemical fungicides applied according to economic thresholds and in rotation or mixture to delay resistance development, thereby maximizing durability and minimizing environmental impact. However, the successful translation of this strategy to the field hinges on overcoming key challenges in formulation stability, scalable production, and seamless integration into existing and chemical-based agricultural practices to mitigate the impact of wheat rusts and safeguard global wheat yields and food security.