Biological control of anthracnose of chilli with rhizosphere and rhizoplane fungal isolates from grasses

Abstract

The fungal species from rhizosphere and rhizoplane of perennial grasses of the Western Ghats of India were studied for their pathogenicity, antagonism in vitro, substrate and root colonization abilities, rhizosphere competence, growth in different soil pH and inoculum shelf-life. Out of 138 non-pathogenic fungal isolates tested, 85 were antagonistic in vitro to chilli anthracnose pathogen Colletotrichum capsici. Fifteen isolates with >60% inhibition zone to pathogen culture had saprophytic and root and rhizosphere colonization abilities. The sorghum grain inocula of test antagonistic fungi- Fusarium oxysporum, Chaetomium globosum and Trichoderma harzianum had the shelf-life of 90 days at 20 ± 2 °C and required optimum soil pH of 6.5. The above fungal isolates when tested for biocontrol of anthracnose disease in greenhouse and field caused reduction in seedling mortality and decreased disease incidence and severity at various plant growth stages and significant reduction in chilli fruit and seed infection. The test antagonistic fungi promoted seedling and mature plant growth and increased fruit and seed yield. Populations of these antagonistic fungi were fairly high in chilli rhizosphere at harvest. The present study indicated that antagonistic fungi from grass rhizosphere and rhizoplane could be used to control anthracnose and promote plant growth, and increase yield of chilli in field.