Chiang Mai Journal of Science

     Among plant par asitic nematodes, Meloidogyne (root-knot nematode) is one of the most economically important pests. The use of chemical nematicides is effective, however, can cause side effects on the environment and human health. For an environmentally friendly approach, the biocontrol methods are focused. This study aimed to evaluate the biological control of native Trichoderma spp. against Meloidogyne incognita (Kofoid and White) Chitwood. It was found that T. virens K1-02 and T. viride Z2-01 inhibited M. incognita egg-hatching by 71.7 and 73.4 %, respectively, and increased the mortality of juveniles by more than 80.0 % at 7 days post-inoculation under laboratory conditions. Regarding pot assays of the Sida tomato plant, both species exhibited the potential to inhibit gall formation and reproduction of M. incognita. Gall and egg mass index were lower in tomato roots treated with Trichoderma spp. than in untreated control. The reproduction factor (Rf) was 5.0 and 3.6 when treated by T. virens K1-02 and T. viride Z2-01, respectively while the untreated control was 12.3. These Trichoderma spp. did not affect tomato root length and plant height. The enzyme assays showed that both Trichoderma species could produce cuticle-degrading enzymes (chitinase and protease), whereas T. viride Z2-01 exhibited the highest activity of protease at 1.7 U/ml. In addition, it could be pointed out that the native Trichoderma isolates killed M. incognita before it invaded the tomato plant which correlated with the low activity of plant response enzymes, peroxidase (POD), and polyphenol oxidase (PPO) in tomato roots. The antagonist potentials of these Trichoderma species could lead to the development of bio-nematicide for controlling root-knot nematode disease.