Seleção de leveduras antagônicas ao Colletotrichum truncatum, agente causal da antracnose em Phaseolus lunatus L.

Abstract

The development of biological control methods is essential for promoting more environmentally sustainable agricultural practices and minimizing the risks to human health. In this context, yeasts have emerged as promising alternatives for biological control owing to their ability to inhibit the growth of filamentous fungi. Anthracnose, caused by the fungus Colletotrichum truncatum, leads to significant losses in Lima bean (Phaseolus lunatus) production, adversely affecting the livelihoods of family farmers in the northeastern region. This study aimed to evaluate the efficacy of antagonistic yeasts in controlling the causal agent of anthracnose in lima beans. The yeasts used in this study were sourced from a collection representing colonizing fruit surfaces. These yeasts were tested in co-cultivation with the pathogen, assessing their antagonistic effects in vitro and their potential to reduce disease severity in leaves. A total of 41 yeasts were screened through in vitro tests, of which eight were selected based on their high percentage of mycelial growth inhibition, both in direct confrontation and through the production of volatile compounds. In greenhouse trials assessing disease severity reduction, yeast application under protective conditions identified isolate P1 as the most effective at inhibiting fungal growth. Interestingly, some yeasts exhibited different results in disease severity reduction compared to their performance in mycelial growth inhibition tests. This underscores the need for further studies to understand better the complex interactions among antagonists, pathogens, and plants, as these factors may influence and modify pathogen development under natural conditions. Keywords: Biological control; Metabolites; Alternative control; Bioinput; Agricultural sustainability.