Biodiversity of Plant Pathogenic Fungi - Kerala Forest Research ...

well as fructifications in culture medium, a freeze microtome (Minotome-Cryostat, IEC,
USA) was also used. The sections of fructifications of various fungi were observed under
Leitz Dialux –20 Microscope and photomicrographs were prepared. Identification of the
fungi up to species level, as far as possible, was made based on their cultural and
morphological characteristics. The fungal isolates which belong to possibly new taxa and
hitherto unpublished were assigned species number as Sp.1, Sp.2, etc. for publication
elsewhere. However, information on the cultural characteristics, morphological and
pathological peculiarities are provided for all such fungi at appropriate places in the text.
All the fungal isolates were pure cultured and assigned KFRI. Culture No. and
maintained in the Microbial Culture Collection Facility at KFRI.
Pathogenicity trials
Pathogenicity of fungal isolates was tested using seedlings of the respective host plants
raised in the glasshouse. As it is not practical to test all the fungi isolated to their
respective host plants to establish the pathogenic status, only selected fungi (rarely
encountered ones, new species and weak pathogens) were screened. Pathogenicity of the
fungal isolates to the respective hosts was tested by using 3-6 month-old seedlings and
spraying conidial suspension (2 x 10 3 conidia/ml of sterile water) of the respective
fungus. Three to five seedlings of the respective host plants were inoculated and the
inoculated seedlings were incubated in humidity chamber (>90% r.h, 26 ± 2 0 C with 12 h
dark and light period). Disease symptoms developed in the host plants were recorded and
fungus was re-isolated from the diseased host tissues and pathogenicity of the respective
fungal species confirmed.
Biodiversity analyses
Numerical data on pathogenic fungi obtained from representative study plots under each
forest ecosystem were pooled and Species richness indices (Margalef’s index and
Menhinick’s index), Species diversity indices (Simpson’s index and Shannon’s index)
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