Author : Pongpan Thienhirun

Summary : Six species of Trichoderma (T. piluliferum, T. hamatum, T. harzianum, T. longibrachiatum, T. aureviride and T. koningii) irradated with ultraviolet (UV) light for various times including 0, 5, 10, 15, 30, 45 and 60 mins. were tested for the efficacy in parasitizing eggs of root-knot nematode (Meloidogyne incognita). Three species, T. piluliferum, T. hamatum, and T. harzianum which were exposed to UV for 30 mins. provided the percentage of infectivity of 49.48, 30.45 and 28.25, respectively. Wildtypes and mutants from each species of Trichoderma selected from those with highest percentage of infectivity were transferred to PDA and PDA supplemented with benomyl (Benlate 50 percent WP) at the rates 5, 10 20 and 40 ppm of active ingredient. Mutants from T. piluliferum and T. hamatum could grow on PDA and PDA supplemented with 5 and 10 ppm benomyl. T. hamatum (wildtype and mutant) could grow on 5 to 40 ppm benomyl. Amounts of chitinase and cellulase enzymes were determined by enzyme activity and enzyme specific activity. T. hamatum (mutant and wildtype) T. piluliferum (mutant) could produce more chitinase than other species. Mutant of T. piluliferum could markedly produce more chitinase as compared to wildtype isolate. Enzyme specific activity of chitinase and cellulase and enzyme activity of cellulase were similar to enzyme activity of chitinase.