Morphogenetic characterization of Fusarium oxysporum associated with storage rot of ginger in Assam and in vitro evaluation of botanicals

Abstract

Post-harvest rot of ginger is an important disease which resulted in huge losses in quality as well as quantity of ginger ultimately leads monetary loss to farmers as well as traders. In study of storage rot of ginger, survey under three agro-climatic zones (Upper Brahmaputra Valley zone, Hill Zone and Lower Brahmaputra Valley Zone) of Assam revealed that Fusarium sp. was majorly associated with storage rot of ginger. Their pathogenicity on ginger was determined and the microbes have been identified based on morphogenetic characterization. Morphological features of the isolate were described and Internal Transcribed Spacer (ITS regions) was used to characterize the isolate at molecular level. Molecular phylogenetic analyses revealed that these isolate was assignable to Fusarium oxysporum. Ten botanicals (Acorus calamus, Allamanda cathertica, Allium cepa, Allium sativum, Curcuma longa, Datura wrightii, Lasia spinosa, Laurus nobilis, Ocimum sanctum and piper betle) were evaluated against the pathogen.Aqueous extracts (20%) of A. sativum, A. cathertica and L. nobilis significantly inhibited the growth of F. oxysporum. These three most effective botanicals were further tested at four different concentrations (5, 10, 15 and 20 per cent) and A. sativum (92.22%) at 20 per cent concentration exhibited highest inhibition followed by A. sativum (84.44%) at 15 per cent and A. cathertica (78.22%) at 20 per cent. This was followed by A. sativum (74.44%) at 10 per cent, A. cathertica (73.33%) at 15 per cent and L. nobilis (72.22%) at 20 per cent.