Leaf blast disease in finger millet [Eleusine coracana (L.) Gaertn.] caused by Bipolaris sorokiniana Sacc.: a histopathological study

Abstract

Finger millet (Eleusine coracana L.) is a staple food in many African and South Asian countries and is ranked fourth among millets produced worldwide. Finger millet crops are affected by a number of diseases, including blast disease, which is the most destructive and widely distributed disease of the world. It is generally caused by Pyricularia grisea (Cooke) Sacc. We observed blast like symptoms in finger millet crops in the field in Doddamaragowdana halli, Mysore District, India. The infected leaves were subjected to analysis to identify the causative agent. Histopathological studies were conducted at different stages of infection (namely 3, 6, 12, 24, 48 till 72 h) and infection process was observed beginning with adhesion of conidia on the leaf surface, production of germ tube, aspersorium formation followed by formation of hyphae and conidia. Based on the morphological characteristics of the colony, conidiophores and conidia as well as by performing Koch’s postulate the organism was identified. Based on our results, the pathogen isolated from the foliar samples of finger millet collected from infected field was identified as Bipolaris sorokiniana Sacc. To our knowledge, this is the first report of blast disease in finger millet caused by Bipolaris sorokiniana Sacc.