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

From the Kerala part of the Western Ghats, so far, a total of 1200 fungal species have been
recorded. If the vascular plant-fungi ratio of 1:6 (Hawksworth, 1991) is applied, there
should be around 24,000 fungal species. If this estimate approximates to the real situation,
it means, more than 95% of the fungal flora of the Western Ghats is yet to be made
known.
Many biodiversity specialists are of the opinion that tropical forests are more species-rich
than temperate forests; thus this may be true for fungi as well. However, this hypothesis
has not been rigorously tested for fungi, although a few comprehensive studies have been
undertaken that provide supportive evidence (Cannon and Hawksworth, 1995;
Hawksworth, 1993). In exploring tropical regions for fungi, it is anticipated that the most
widespread and common species in a site will tend to be found first. Most likely, such
species have been collected before and have been described already. However, the longer
the time spent on intensive exploration, the more are the species discovered.
The known 200,000 species of vascular plants continue to serve as the major reservoir of
novel fungi. It has been estimated that there may be around 270,000 species of plantpathogenic
fungi in the tropics (Shivas and Hyde, 1997)! In the tropics, it is particularly
difficult to ascertain patterns of species richness. Batista and coworkers (1995) recorded
3,340 fungi from Brazil associated with 523 plant species, equivalent to an average of 6.4
fungi per host plant studied. Such data were not collected for an analysis of species
richness and are difficult to assess, because not all plants were studied and plant species
without fungi were not listed.
Plant pathogenic fungi include a very large and heterogeneous group of organisms that
occupy positions of great economic importance in agriculture, forestry and natural plant
communities. More than 8000 species of fungi have been reported as causing diseases and
disorders in plants. They show an enormous diversity in life-history strategies and the
ways in which they interact with their hosts. These interactions range from species that
establish perennial, systemic infection that castrate their hosts, to pathogens that kill their
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