In vitro and in vivo evaluation of microbial agents for management of rice blast disease in Tanzania

Abstract

Evaluation of two microbial agents, Trichoderma asperellum and Bacillus subtilis and fungicide Linkimil 72 WP against rice blast disease, Pyricularia oryzae were done in a laboratory and pot experiment. Dual inoculation of T. asperellum, B. subtilis and Linkimil 72 WP caused significant inhibition of radial growth of P. oryzae. Both T. asperellum and B. subtilis showed over 75% inhibition of radial growth (PIRG) compared to Linkimil 72 WP with PIRG range of 21-23 % and control with 0 %. In a pot experiment, 70 % reduction in disease incidence was in plants treated with T. asperellum followed by B. subtilis (51.5 %) and Linkimil 72 WP (26.5 %). There was a 44.5 % decrease in disease severity in plants treated with Linkimil 72 WP compared to plants treated with T. asperellum (35.6 %) and B. subtilis (29.1 %). The number of lesions per leaf was low on rice plants treated with T. asperellum followed by Linkimil 72 WP and B. subtilis. T. asperellum and B. subtilis used in this study had shown a high antagonistic capacity against P. oryzae and they can be recommended as part of integrated management of rice blast disease.