Biocontrol of water hyacinth using fungal pathogens
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Date
1997
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Department of Plant Pathology, College of Agriculture, Vellayani
Abstract
Detailed study was conducted on the host range of the
already identified fungal pathogens of water hyacinth viz.
Colletotrichum
gloeosporioides,
Fusarium
eguiseti
and
F.pallidoroseum
on thirty
cultivated
plants
including
vegetables, pulses and oil seeds, field crops, fruits and forest
crops and ornamental plants and forty one common weed plants
which are seen in and around water ways infested with water
hyacinth.
It was observed that C. gloeosporioides could infect
amaranthus, bhindi, chilli, Euphorbia hirta, Hydrocotyl asiatica
and Phyllanthus niruri. Of the thirty cultivated plants and
forty one weed plants tested F. eguiseti was seen to be
pathogenic
to
amaranthus,
Amaranthus
viridis,
Commelina
. bengalensis, C. jacobi and Monochoria vaginalis.
F. pallidoroseum could produce symptoms on napier grass, Axonopus sp., boerhaavia diffusa, C.benghalensis, C.jacobi, Echinochloa colonum, Euphorbia hirta, Justicia diffusa, J.prostrata, M.vaginalis and Oldenlandia umbrellata and Scorpia dulcis.
For the effective destruction of the weed, lxl011
spores per ml concentration of Q. gloeosporioides, E. eguiseti
and F. pallidoroseum were found to be more effective than lxl09
and lxl010 spores per ml concentration.
Cell free metabolites of the pathogenic fungi were
found to produce symptoms on water hyacinth plant. Metabolite
produced by E. pallidoroseum caused considerable damage than by
E.equiseti and C. gloeosporioides.
When pathogens were applied singly and in combination
on water hyacinth it was observed that the combined application
of F. pallidoroseum and F. equiseti followed by F. pallidoroseum
alone gave maximum intensity of infection. Eventhough
C. gloeospoirioides gave least intensity of infection it can be
used as a co-pathogen with E. eguiseti.
Metabolite of the pathogens individually and in combination when applied on healthy water hyacinth plants, maximum damage was caused by F.pallidoroseum alone and the combination of metabolite of three fungi viz. C. gloeosporioides,F equiseti and F. pallidoroseum. Least damage was caused by metabolite of C. gloeosporioides.
An experiment was conducted to find out suitable carrier materials for the mass multiplication and storage of pathogen. It was observed that for C. gloeosporioides maximum sporulation was in water hyacinth leaf followed by guinea grass straw and rice bran. But the spore viability was maximum for rice straw, and on coir pith. Maximum infection was caused by fungus grown on guinea grass straw and rice straw.
In the case of E. equiseti spore counts was higher in
guinea grass straw followed by coir pith. The spore germination
was maximum in rice bran and coir pith. Maximum infection was
produced by the fungi on guinea grass straw, coir pith and
waterhyacinth leaf.
E. pallidoroseum produce maximum number of spores on
rice bran followed by guinea grass straw. It was observed that
the germination percentage of spores were maximum on coir pith.
Out of the six carrier materials used the fungus produced maximum
infection when grown on rice bran and guinea grass straw.
In the study for testing the storage life of
metabolities, it was observed that the efficiency to produce
symptom was reduced on storage in the case of C. gloeosporioides
and E. pallidoroseum whereas for E. eguiseti on storage the
effeciency of the metabolite to cause damage increased.
Metabolite stored on refrigerated condition performed poorly for
all the three fungi.
Different methods of application of the three fungi
were tried. Of the five treatments, placement of bits and
dusting the inoculum along with the carrier materials produced
maximum infection.
In the experiment conducted to characterize the toxin presented in the cell free metabolite of pathogenic fungi, observed the presence of Fusaric acid in the metabolite of Fusarium spp.
Description
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Citation
171304