First record of Alternaria macrospora MKP1 causing leaf spot disease on Parthenium hysterophorus from India

In the years 2012-14 a series of extensive surveys for natural enemies of parthenium were conducted in Haryana. During survey, a leaf spot disease has been regularly reported on congress grass at different parts of the Kurukshetra and its adjoining areas. The fungal pathogen was isolated from the affected parts of parthenium leaves and on the basis of cultural, morphological and molecular characteristics, was identified as Alternaria macrospora MKP1. Koch’s postulate was performed and found satisfactory for the isolate and proved to be pathogenic to this weed. The growth of A. macrospora MKP1 was studied on eight different media and it exhibited varying degrees of growth on different media. The literature survey indicates that A. macrospora has never been reported on the parthenium weed and it is the first report of occurrence of this pathogen causing leaf spot disease on parthenium weed from the world.