Each fresh sample was dipped in 75% ethanol solution for 60 s for surface disinfection. The sample was then placed in PDA (potato dextrose agar) medium and kept at 28 °C and 70% humidity. Single hypha of any resulting fungal mycelia growing on the plate was transferred to new plate. The purified isolates were then preserved at 4 °C until further experiment. Stock isolates were stored at −20 °C and −80 °C respectively.