Nemato-toxic potential of Trichoderma harzianum and T. viride extra-cellular metabolites and Annona glabra crude extraction on Meloidogyne incognita infestation

Root-knot nematode, Meloidogyne incognita (Kofoid and White) is one of the most destructive plant parasitic nematode species in almost all agriculture and horticulture crops in Sri Lanka. Biologically sound controlling measures against this nematode species has been attempted from long past with ambiguous efficacy. This paper highlights the nemato-toxic potential of crude leaf extract of Annona glabra, and extracellular metabolites of Trichoderma harzianum and T. viride on root-knot nematode species, Meloidogyne incognita infesting in spinach plants under semi-field conditions. Results revealed that nematode infested plants treated with T. harzianum extract showed a significantly higher plant growth together with reduced root galling compared to that of T. viride and A. glabra crude extract. Both T. harzianum and T. viride treatments significantly increased the root growth of the nematode infested plants compared to that of A. glabra crude extract. Annona glabra crude leaf extract at the rate of 125 g/L and fungus mycelium of T. viride and T. harzianum at the rate of 140 mg/L and 100 mg/L respectively resulted the highest nemato-toxic potential against M. incognita. This study concludes positive effect of antagonists tested against M. incognita and suggests that activity of lytic enzymes of T. harzianum and T. viride has enhanced the nemato-toxic effect.