Evaluation of Botanicals Against Colocasia Blight Caused by Phytophthora colocasiae Raciborski

Colocasia leaf blight is the most devastating disease of colocasia incited by oomycetous pathogen Phytophthora colocasiae Raciborski. Use of chemicals in the management of this disease may lead to health and ecological hazards thus in the present investigation, the efficacy of botanicals were evaluated both under in-vitro and in-vivo conditions against colocasia blight. Four different botanicals which included leaf extracts of Azadirachta indica (neem), Melia azedarach (drek) and botanical formulations of lantana ark and dashparni were evaluated against P. colocasiae at four concentrations ( 5, 10, 12 and 15 per cent). Lantana ark was found to be most effective under in-vitro as well as in-vivo conditions at 15 per cent concentration resulting in 72.3 per cent mycelial growth inhibition and 65 per cent disease control, respectively followed by Azadirachta indica.