Effect of trichoderma viride strain NRRL 6418 and trichoderma harzianum (hypocrea lixii TWC1) on livistona rotundifolia root knot nematode meloidogyne incognita

Abstract

Meloidogyne incognita is a causal agent of root knot disease in many plants. This nematode causing damage in foliage nurseries of Livistona rotudifolia cultivated countries especially in Sri Lanka. Due to importance of this disease in foliage nurseries and impossibility of using chemical control against this damaging agent in this research, two species of Trichoderma viride strain NRRL 6418, Trichoderma harzianum (Hypocrea lixii TWC1), as an antagonist fungi against M. incognita were isolated and identified from foliage nursery in Sri Lanka. The efficacy of these bio control agent against M. incognita were investigated in vitro and in vivo condition. Thus, this research was carried out to investigate the mechanisms of action by which Trichoderma sp. antagonizes M. incognita in vitro and the efficacy of application of a conidia suspension of Trichoderma for control of M. incognita root knot disease under field conditions. In vitro, the antagonistic behavior of Trichoderma sp. resulted in the overgrowth of M. incognita by Trichoderma sp., while the antifungal metabolites of Trichoderma sp. prevented the hatching of M. incognita eggs and the growth of the second juveniles. Light microscope observations showed the evidence that mycoparasitism contributed to the aggressive nature of the tested isolate of T. viride NRRL 6418 and T. harzianum(Hypocrea lixii TWC1) against M. incognita female body and egg masses. Under field conditions, drenching of a conidia suspension of T. viride NRRL 6418 and T. harzianum (Hypocrea lixii) at lX10)14) spore mL-1 significantly reduced the disease incidence (DI) in the plant roots and also significantly increased the plant growth of L. rotundifolia. © 2011 Academic Journals Inc.