Pathogenesis Studies of Marssonina coronaria (Ellis & J.J. Davis) J. J. Davis Causing Premature Leaf Fall of Apple

摘要

Marssonina leaf blotch caused by the fungus Marssonina coronaria (Ellis & J.J. Davis) J.J. Davis causing premature leaf fall is one of the major economic constraint which hampers apple production in India. Seven isolates of Marssonina coronaria were isolated and evaluated for their pathogenesis on healthy potted plants on three different cultivars, i.e. Starking Delicious, Tydeman's Early Worcester and Granny Smith by spraying with conidial suspension harvested from pure culture of the isolates. Pathogenesis studies revealed highest percentage of conidia germination of Marssonina coronaria on the leaves of Starking Delicious and minimum in cultivar Granny Smith cultivar. Shortest incubation and latent periods were recorded in cultivar Starking Delicious and maximum incubation were recorded in cultivar Granny Smith with minimum production of spores per ml ranging showing it to be moderately resistant to all the isolates of Marssonina coronaria included in the study.