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Biocontrol of rhizome rot of ginger using selected aqntagonists
Rhizome rot of ginger cas used by Pythium aphantdermatum (Edson) Fitzpatrick is one of the most destructive diseases of ginger in Kerala. The pathogen was isolated and its pathogenecity was established by Koch's postulates in ginger variety Rio-de-Jenerio. Among the various food bases evalua...
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| Format: | Ph.D Thesis |
| Sprog: | Undetermined |
| Udgivet: |
Vellanikkara
Department of Plant Pathology, College of Horticulture
1999
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| Summary: | Rhizome rot of ginger cas used by Pythium aphantdermatum (Edson) Fitzpatrick is
one of the most destructive diseases of ginger in Kerala. The pathogen was isolated and
its pathogenecity was established by Koch's postulates in ginger variety Rio-de-Jenerio.
Among the various food bases evaluated, for the mass multiplication of selected
antagonists, rice hull was found to be significantly superior to all others to obtain
maximum growth for Trichoderma viride and Aspergillus flavus. For Aspergillus niger,
rice bran was found to be significantly superior.
The results on the effect of various treatments on germination showed that there
was no significant difference among the treatments. The effect of antagonists on the pre-
emergence rotting and post-emergence rotting (rhizome rot) were studied. In plots where
antagonists (T viride, Aflavus or A. niger) or fungicides (mancozeb or copper
oxychloride) were applied either as seed treatment or as soil incorporation at the time of
planting, the pre-emergence rotting was not observed. The plot in which the antagonists
T. vtride, A. mger and At flavus were applied in combination at 60 and 120 OAP, recorded
the minimum rhizome rot incidence compared to other treatments. The plots in which the
antagonists were applied twice, i.e., 60 and 120 OAP, the rhizome rot incidence was
minimum compared to the plots with only one time application of antagonists. The
maximum population of the pathogen P. aphanidermatum. was observed in plot where
A. flavus was applied in combination with mancozeb.
The multiplication of selected antagonists, 7: viride, A. flavus and A. niger in soil
was found out by estimating their population at different stages. The population of
T. virtde was maximum in plots where it was applied in combination with mancozeb in
most of the period. The soil application of the combination of antagonists T. viride,
A. flavus and A. niger did not affect the multiplication of anyone of them in soil. In
general, soil incorporation of antagonists was found to helping in their mulitplication
profusely compared to the seed treatment. The incorporation of the antagonists A. flavus
and A. niger to the plots, twice was found to be superior than applying them only once,
for getting maximum multiplication of propagules in soil. The result on the compatibility
of antagonist with fungicide in field condition revealed that the antagonist T viride was
quite compatible with mancozeb whereas A. flavus and A. niger were compatible with
both fungicides tested (mancozeb and copper oxychloride). The treatments which was
found to be superior in minimising the incidence of rhizome rot of ginger viz., T 16 (soil
incorporation of T vir/de, A. niger at 60 and 120 DAP) and TI9 (soil incorporation of
I: viride, A. niger and A. flavus) also recorded the maximum yield of ginger.
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