Suppression of Collar-rot caused by Sclerotium rolfsii Sacc. in chilli by antagonistic bacterial treatments

Abstract

Chilli (Capsicum annuum L.) is an important crop in Sri Lanka. However, chilli cultivation is severely affected in many areas due to several soil-borne pathogens. Sclerotium rolfsii Sacc. has been identified as one of the major pathogens that even attack mature plants. Success of control of the pathogen by using merely fungicides is not promising. Rhizobacteria isolated from healthy chilli plants were screened for antagonism against S. rolfsii and isolates of a Pseudomonas spp. and a Bacillus spp. were found to be highly effective on plate assays. Doss-response analysis showed that there is a linear relationship between inoculum dosage and disease incidence. Seed bacterization with individual biocontrol agents significantly reduced the disease incidence in chilli compared to the non-bacterized control and introducing bacterial isolates to root system prior to transplanting of seedlings further enhanced the seedling protection from S. rolfsii infection.