Etiology and management of rhizome rot disease of banana

Abstract

Rhizome rot disease of banana is one of the most serious diseases of banana In Kerala.The pathogen was isolated from infected rhizomes of banana var. Nendran and the pathogenicity was established after standardising the method of inoculation .. The symptomatology of the disease was studied in detail under natural field conditions and under artificially inoculated controlled conditions. The salient symptoms of the disease were flaccidity and yellowing of leaves and soft rotting of the rhizome. Based on the morphological, cultural, biochemical, physiological and molecular characters, coupled with its pathogenicity, the pathogen causing rhizome rot disease of banana var. Nendran was identified as Erwinia carotovora. Studies were conducted on the host range of the pathogen on five hosts viz. heliconia, canna, ginger, turmeric and colocasia under field conditions. The results revealed that the pathogen failed to infect these hosts. Studies on soil survival of the pathogen revealed that the pathogen survived in the sterilized soil in the presence of diseased rhizomes for 180-185 days. Out of the 240 accessions of banana screened for resistance to rhizome rot disease under natural field conditions, the genome AAB is found to be the most susceptible one among the genornes screened. The variety Poppoulu (AAB) was found to be the most severely infected one. The commercial variety of Kera1a viz; endran was also found to be highly susceptible to the disease. In vitro inhibitory effect of antibiotics, fungicides, botanicals, and bioagents on the growth of the pathogen was tested. Among the fungicides, fytolan at 0.4 per cent concentration gave the maximum inhibition followed by fytolan at 0.3 per cent. Among the antibiotics tried, streptocycline at 300 ppm was found to be the most superior one. Garlic extract at 100 per cent concentration was the best botanical for inhibiting the pathogen. Pot culture experiment on the management of the disease revealed that among the six treatments given, fytolan at 0.4 per cent and streptocycline at 300

ppm were found to be the most effective treatments in controlling the rhizome rot disease of banana. Garlic extract at 100 percent concentration was also found to be effective in managing the disease under field conditions, which was on par with Pseudomonas flourescens (T2) and bleaching powder (Tl).