Root-knot nematodes of the genus Meloidogyne badly affect crop production worldwide and cause huge yield losses. Among the known root-knot species, Meloidogyne incognita is by far the most destructive, widely distributed and the most dominant and prevalent. In the present study, the efficacy of a biological control agent, Trichoderma harzianum and an antagonistic plant, Azadirachta indica was tested against M. incognita on tomato. The antagonistic fungus and plant caused significant hatching inhibition and larval mortality of M. incognita. The hatching inhibition and mortality was the maximum at 100% concentrations of both the agents while the minimum inhibition and mortality was obtained at 25% concentration. No statistical difference was observed between T. harzianum and A. indica in causing hatching inhibition and larval mortality. Numbers of galls, egg masses and reproductive factor were reduced significantly as a result of A. indica and T. harzianum applications. The reductions in these parameters were more pronounced where both the agents were integrated and resulted to the maximum where both the agents were mixed at the highest concentrations. The reductions in galls, egg masses and reproductive factor were found inversely proportional to the concentrations of A. indica and T. harzianum. Similarly, all the concentrations of A. indica when integrated with T. harzianum increased plant height and fresh shoot weight significantly over control. The increase in these parameters was directly proportional to the concentrations of A. indica leaves and T. harzianum. A. indica amendments proved at par with those of T. harzianum. The maximum increases in these parameters were obtained where A. indica leaves were mixed at the rate of 50 g with 6 g of T. harzianum. The amendments also showed significant effects on root weight. The maximum decrease in root weight was observed where both A. indica and T. harzianum were mixed at the highest concentrations. The root weight decreased with an increase in concentration and was found inversely proportional. It is therefore, recommended that the integration of antagonistic plants with the antagonistic fungi may be useful for the better control of plant parasitic nematodes.
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