Abstract:
Anthracnose and rust are widely spread diseases in leaves, ripening and ripe fruits of
uguressa (Flacourta indica (Burmm.F). Merr) in Sri Lanka. An investigation carried out to
determine the effect of fruit and leaf exudates for the development of anthracnose and rust
pathogens in fruits and leaves of uguressa. The casual agent of anthracnose (Colletotrichum
gloeosporioides) and rust (Uromyces species) diseases were isolated and identified using
morphological features of culture media, microscopic observations and Koch’s postulation.
Exudates obtained from fruits of all maturity stages and leaves were separated into two
fractions that are soluble in ether and water to investigate the effect fruit and leaf exudates
for the differentiation of spores of both fungi. Conidia of C. gloeosporioides germinated and
produced appressoria within 22 hours on fruit exudates of all maturity stages of uguressa
fruits. The highest stimulation of conidia differentiation of C. gloeosporioides was observed
in fruit exudates of ripe fruits which are highly susceptible for the anthracnose disease.
Chemical substances found in both water soluble and ether soluble fractions enhanced
conidia differentiation of C. gloeosporioides. Significantly highest lesion development of
anthracnose found on ripe fruits compared to mature and immature fruits. Higher conidia
differentiation of C. gloeosporioides was observed in original exudates of leaves compared to
ether and water fractions. There was no effect of leaves and fruit exudates for germination on
urediospores of Uromyces species. The study revealed uguressa fruits and leaf exudates have
chemical substances to stimulate differentiation of spores of C. gloeosporioides and lesion
development while there is no any chemical substances that stimulate the differentiation of
Uromyces sp
