EFFICACY OF SOME BIOCONTROL AGENTS IN CONTROLLING Ralstonia solanacearum CAUSING BROWN ROT OF POTATO

Abstract

ABSTRACT An experiment was conducted to investigate symptom, detection of pathogen and find out the efficacy of some BCAs on disease suppression as well as agronomical performance of potato. The experiment was carried out in a potato field in Gowalkhali of Sirajdikhan, in Munshiganj district and the in vitro research had been done at Disease Diagnostic Laboratory of the Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka from November 2019 to October, 2020. Four BCAs namely Greenstree, Neutrase, ACI Bamper Trico , Biocoa which contained microbial agent called Bacillus subtilis, B. amyloliquefaciens, Trichoderma sp. and mixer of microbes respectively, were used as treatment. Each BCAs were used as soil application and foliar spray. Significant pathogen Ralstonia solanacearum was identified by morphological, biochemical and cultural test. Field application of the BCAs as spray and soil treatments significantly reduced wilting and the brown rot incidence. The brown rot incidence was in the range from 2.8 % to 35%. Application of Bacillus subtilis soil application showed the lowest incidence. The BCAs treatments improved the vegetative growth parameters such as plant height, leaf number/plant and average tuber weight compared to the control plants. The maximum number of leaves per plant was found in Bacillus subtillis soil application (19.86). Plant height was also high on this treatment. Again, the average weight of tuber were found in Bacillus subtillis in soil application(39.3g) while highest number of tuber per hill was found in foliar spray of Trichoderma(8.18). This experimental results suggested that the soil application of BCAs were the best to protect the potato tubers against bacterial brown rot disease and gave significant effect on the physiological growth and development of potato tubers. The soil applications of B. subtilis is the most promising BCA whose antibacterial effect reduced brown rot and promote tuber growth and development.