Misconceptions and advances in sustainable biocontrol of Botrytis cinerea in grapevines. A review

Gray mold, caused by the necrotrophic fungus Botrytis cinerea, is among the most destructive diseases of grapevine, with yield losses that can exceed 40–70 % depending on cultivar, climate and post-harvest handling. Growing fungicide resistance and policy-driven reductions in the use of synthetic pesticides further tighten control options, creating an urgent need for eco-friendly alternatives. Biological control agents (BCAs), including antagonistic yeasts, bacteria and filamentous fungi, address this need; however, their field performance is often inconsistent and misconceptions persist about pathogen ecology, optimal application timing and regulatory requirements. This review consolidates recent progress in sustainable biocontrol of gray mold and analyses how four biocontrol-enhancing attributes: (i) antagonist diversity, (ii) solo versus consortium applications, (iii) protective formulations, and (iv) risk-aligned spray timing guided by disease-forecast models. The key findings are as follows: 1) new insights into multitrophic interactions now guide targeted strain selection; 2) precision-application technologies align BCA delivery with pathogen risk windows, reducing product losses; 3) innovative formulations and well-designed microbial consortia extend persistence under field stress; 4) epidemiological modelling reveals climate-driven shifts in gray-mold pressure and their implications for BCA success; and 5) adoption barriers can be lowered through harmonized regulation and grower education. Combining these attributes results in mean reductions in bunch-rot severity, outlining a credible pathway toward reliable, pesticide-sparing management of B. cinerea and supporting the transition to more sustainable viticulture.