Worm Power Against Fungal Diseases in Aroids: Prospects and Future Strategies

Abstract

Organic growers have limited options for plant disease control since most of the effective fungicides  are synthetic, toxic and potentially polluting. Vermicompost and vermiwash have been widely explored  as eco-friendly options for controlling plant diseases. We explored the possibility of utilizing vermicompost  to manage Phytophthora colocasiae and Sclerotium rolfsii that cause taro leaf blight and collar rot of  elephant foot yam, respectively. Microbial diversity was assessed in terms of quality and quantity in  35 vermicompost samples collected from different parts of the country. The distinct isolates were  screened against the target pathogens under in vitro conditions. Potent organisms were identified byITS and rRNA sequencing. Induced systemic resistance (ISR) was quantified in terms of phenol content,  chitinase and glucanase activities. The variability in disease suppression by various vermicompost  samples was studied under in vitro conditions. Pot culture studies were conducted in taro and elephant  foot yam for two years to assess the potential of vermicompost/vermiwash for disease suppression. A  total of 309 culture dependant isolates of vermicompost origin were obtained and 18.9% and 36.4%  of these organisms showed >50% inhibition against S. rolfsii and P. colocasiae, respectively. The  disease suppression potential varied with the source of vermicompost. Vermicompost/ vermiwash treated  plants showed <10% TLB incidence and 0-50% collar rot incidence. Yield increase of 14.70 % was  also noted in both crops. There is scope for utilizing vermicompost for eco-friendly management of  taro leaf blight and collar rot of elephant foot yam.