The inhibition effect of secondary metabolite of Paecilomyces lilacinus against Fusarium oxysporum

An investigation was carried out to examine the effect of the secondary metabolite extracted from Paecilomyces lilacinus on Fusarium oxysporum Schl. The results showed that the secondary metabolite at different concentrations, different culturing terms and cultured by different media would express different inhibiting results against the spore germination and colony growth of Fusarium oxysporum. Judged by appearances, the treated colony grew slowly and badly-distributed on the media. Studied on effect of different concentrations on the inhibition efficiency had been carried out, results showed that the inhibited rates increased along with the concentration increasing. When treated with concentration of 1%, the inhibition rate was 42.78% and treated by 5% secondary metabolite after 7d, the inhibition rate was 80.56%. The inhibition results of the antagonistic secondary metabolite cultured at a constant term of 1-11d had been investigated. Tests result showed that treated with antagonistic secondary metabolite cultured at a constant term of 4-10d, the relative inhibiting rates of all treatments were above 70% at 4% concentration after 7d. But the relative inhibiting rates gone down by 48.49% when treated with 11d secondary metabolite. Another study was conducted to compare the antagonistic efficacy of secondary metabolite cultured by different media against Fusarium oxysporum. When treated with secondary metabolite cultured by Czapek, PDA and Martin-Johnson media, the highest inhibiting rate to colony and sporulation were over 72% and 90% respectively, meanwhile the data tested by LSD there were no significantly differences between the antagonistic result of Czapek culture and hymexazol (400×) treated after 7d. It seems that Paecilomyces lilacinus strain NH-PL-03 can be used as biological agent against Fusarium oxysporum.