The Potential of Soil Bacteria and nanochitosan in inhibiting Colletotrichum sp. Fungi

Abstract

Colletotrichum sp. is the main pathogen causing anthracnose in horticultural crops, especially chili peppers, which causes losses in yield and production quality. The use of synthetic fungicides still dominates the control of this disease, but causes problems with residues, pathogen resistance, and environmental impact. Environmentally friendly alternatives based on biological agents and nanomaterials are needed for sustainable solutions. The methods used in this study evaluated the potential of soil bacteria as antagonistic agents and nanochitosan in inhibiting the growth of Colletotrichum sp. Bacterial isolates were obtained from the rhizosphere of healthy plants, selected based on antifungal activity, and tested for antagonism in vitro using the dual culture method. Nanochitosan was applied at concentrations of 0.2–1.5% to observe its effect on mycelium growth. The results showed that several soil bacterial isolates were able to produce significant inhibition zones with an inhibition percentage of >30%. Nanochitosan treatment effectively slowed colony growth and disrupted hyphal morphology. The combination of antagonistic bacteria with nanochitosan produced a synergistic effect with a higher inhibition rate than either treatment alone. Therefore, the integration of soil bacteria and nanochitosan has great potential to be developed as an innovative, environmentally friendly, and sustainable biofungicide formulation for controlling anthracnose disease in horticultural crops