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Updated: 04-07-13

Managing the root diseases of okra with endo-root plant growth promoting Pseudomonas and trichoderma viride associated with healthy okra roots

SAIMA AFZAL¹, SAMRAH TARIQ¹, VIQAR SULTANA², JEHAN ARA³ AND SYED EHTESHAMUL-HAQUE¹

Abstract: Okra [Abelmoschus esculentus (L.) Moench] is an important vegetable crop is grown world wide including Pakistan. However, diseases are the limiting factor in okra production.  In Pakistan okra crop is attacked by various soilborne plant pathogenic fungi like Macrophomina phaseolina, Rhizoctonia solani, Fusarium spp., and root knot nematodes Meloidogyne spp. Considerable evidence has been accumulated in recent years to support and identify the benefits associated with the use of endophytic bacteria and fungi in crop protection. In this study some strains of endophytic fluorescent Pseudomonas isolated from roots of healthy okra plants were identified as Pseudomonas aeruginosa. The P. aeruginosa isolates showed significant activity against root rotting fungi and root knot nematode in vitro by producing zone of inhibition against test fungi and killing 2^nd stage juveniles of root knot nematode at varying degrees. In screen house experiment, application of some potential strains of P. aeruginosa alone or with Trichoderma viride, an endophytic fungus and biocontrol agent  showed significant biocontrol activity against M. phaseolina, R. solani, F. solani, F. oxysporum and Meloidogyne javanica, the root knot nematode infecting okra roots. Application of most of the P. aeruginosa isolates alone or with T. viride showed positive impact on plant growth by improving plant height, fresh shoot weight and root length. Endophytes colonize an ecological niche similar to that of phytopathogens and biological control with endophytes offers an effective strategy for pest management.

¹Agricultural Biotechnology & Phytopathology Laboratory, Department of Botany, University of Karachi, Pakistan

²Biotechnology & Drug Development Laboratory, Department of Biochemistry, University of Karachi, Pakistan

³Post-harvest Technology Laboratory, Department of Food Science & Technology, University of Karachi, Karachi-75270, Pakistan