Abstract
The present study was undertaken to screen the antagonistic potential of sixteen rhizospheric fungal isolates against selected pathogens of cowpea viz.M. phaseolina, R. solani and F. solani by dual culture technique in lab condition. Among the rhizospheric bioagents, isolate of T. harzianum (T16), T. viride (T13), T. pseudokoningii(T10), T. koningii(T8), A. niger(T6) and of A. flavus (T3) proved to significantly most effective in reducing the radial growth of M. phaseolina, R. solani and F. oxysporum there by resulting in maximum per cent inhibition over control. The most effective bioagent against M. phaseolina, R. solani and F. oxysporum wasT. harzianum followed byT. viride.A. flavus was least effective against all the three test pathogens. It was also noted that all the fungal isolates visualized an increasing rate of percent inhibition in growth of M. phaseolina, R. solani and F. oxysporum in subsequent hour of inoculation.
Plant diseases mainly caused by fungi causes various losses to cowpea crops. The fungus Macrophomina phaseolina, Rhizoctonia solani and Fusarium oxysporum are one of the most widespread and destructive plant pathogens causing dryrootrot/root rot in cowpea (Gokulapalan et al., 2006, Mohamedy et al. 2006). The losses ultimately result in reduced food supplies, poor quality of agricultural produces besides hardship to growers and processors and ultimately higher prices. Hence, the management of plant diseases is an imperative need in the present scenario to meet the increasing demand for the continuous and healthy food supply for an ever-increasing human population. Several methods like cultural, chemical, biological and genetic manipulations are being employed to minimize the losses caused by the plant pathogens. However, biocontrol is the most cheaply safer and eco-friendly. Plant root and their immediate environment, the rhizosphere are colonized by variety of organisms (Curl and Truelove, 1986; Sindhu et al., 1997).
Keywords
Rhizosphere, Fungal Bioagents, Antagonism
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