Sam Raj, JSukumara Varma, AKAU2020-05-272020-05-271967http://krishikosh.egranth.ac.in/handle/1/5810146527PGCultural, physiological and pathogenicity studies of Alternaria species causing leaf spot disease on seven different host plants have been made. of these Hibiscus Rosa-sinensis is a new record for Alternaria in India. All the isolates grew and sporulated on the different solid media tried. But grouth and sporulation on potato dextrose agar were found to be uniformly good.Minimum radial growth of all the isolates was obtained on their respective host leaf extract agar media. Sporulation was also satisfactory in this media. The isolates from Basella and on onion showed pigment production on Czapek's agar mediumenThesis