Pathogenicity of the pathogen isolated from
different samples was tested through Koch’s postulate.
Different host plants such as tea, coffee, mango, citrus
and guava were selected for the study. Tea plants were
treated as primary host and other plants were treated as
secondary host. Ten healthy plants were selected from
each variety for the study. Mature leaves of two year old
plants were wiped thoroughly with sterile water and the
algal filaments were scrubbed over the leaf surface. The
inoculated plants were then covered with polyethylene
bags to maintain 100% relative humidity and kept under
green house condition to develop lesions. Symptoms were
recorded after three months of incubation.