Strategies for the Management of Leaf Blight Disease Caused by Alternaria alternata in Gloriosa superba (L.)

Abstract

Leaf blight caused by Alternaria alternata (Fr.) Keissler is a severe disease of Gloriosa, causing severe yield loss in every part of Gloriosa growing areas of Tamil Nadu. The foliar pathogen was isolated from disease-infected leaves and proved its pathogenicity. Further, the molecular analysis of the pathogen using 18S rDNA confirmed the pathogen as Alternaria alternata. Attempts were made to explore the biocontrol agents and fungicides for the management of leaf blight incidence under field conditions. Four field trials conducted from 2014 to 2018 revealed that foliar application of talc-based formulation of Bacillus subtilis significantly reduced the leaf blight incidence and increased the seed yield under field conditions. Besides, prophylactic application of these biocontrol agents has also increased the plant growth parameters like plant height, number of flowers/plant, no. of pods/plant and number of seeds/pod. Similarly, foliar application of chlorothalonil (0.1%) and mancozeb (0.2%) was also credited to managing the leaf blight disease under field conditions.