Biological Control of Root-Knot NematodeMeloidogyne javanica, using Trichoderma harzianum i25 and investigation on the plant defense compounds flactuations on tomato

In this study, the bio-control activity of Trichoderma harzianum i25 on root-knot nematode Meloidogyne javanica in the laboratory and greenhouse conditions and its ability to induce biochemical defense enzymes such as peroxidase (POX) and polyphenol oxidase (PPO) and total phenol on tomato were investigated. At first, the nematode by the help of morphological and molecular characters and then fungal isolate using morphological one were identified. Infection ability of fungal isolate on the eggs of M.javanica and effects of fungal culture filtrate on egg hatching and mortality of M. javanica juveniles (J₂) were tested in vitro experiment. In the greenhouse experiment, effect of the fungus on tomato plants growth parameters as well as nematode population examined. Also in another experiment, host plant roots at 6 leaf stage were inoculated with fungal spore suspension and nematode as well and POX, PPO and total phenol activity measured after 1 to 8 days of inoculation. Results indicated that the fungal isolate prohibited larval egg hatching and increased nematode mortality and also parasitized the eggs in the egg masses. In the greenhouse, the fungal isolate reduced disease and suppressed nematode population at 85% and also the fungus increased host plant growth parameters. The amount of POX and PPO increased and this increase was at its max. in the 4^th and 5^th day of the infected plant treated with the fungus. Inoculation of the tomato seedlings with the fungus increased the total phenol amount in the leaves in which the highest amount recorded in the infected fungus treated plant on the 8^th day. Results indicated the potential of the isolate i25 in nematode bio-control.