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EFFICACY AND PERSISTENCE OF MICOBIAL ANTAGONISTS AGAINST SCLEROTIUM
ROLFSII UNDER FIELD CONDITIONS
FOUZIA YAQUB*
AND SALEEM SHAHZAD
Abstract:
Sclerotium
rolfsii
showed significant negative effect on plant growth due to severe root
colonization, whereas, presence of the microbial antagonists showed
significant positive effect on plant growth by reducing the colonization
of roots by S. rolfsii. Highest root colonization by S.
rolfsii and significant reduction in plant growth were observed in
sunflower and mungbean plants growing in soil artificially infested with
sclerotia of S. rolfsii. Use of biocontrol agents in S.
rolfsii infested soil showed significant reduction in Root
Colonization Index accompanied by increase in plant growth.
Bradyrhizobium sp., was found most effective (p<0.01) followed by
Rhizobium sp., Trichoderma harzianum, T. pseudokoningii, T.
polysporum and T. virens.
Efficacy of biocontrol
agents was comparatively suppressed in S. rolfsii infested soil
as compared to non-infested soil. There was no significant difference in
plant length in infested and non-infested soils where biocontrol agents
were used. However, plant weight was less in infested soils as compared
to non-infested soils. The microbial antagonists persisted in the soil
and produced similar results when mungbean and sunflowers were re-sown
in the same plots.
Pest & Disease Research
Lab., Department of Agriculture and Agribusiness Management, University of Karachi,
Karachi–75270, Pakistan
*E-mail:
fouziayaqub_biologist@yahoo.com
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