Optimal media for selective isolation of entomopathogenic fungi

다국어 초록 (Multilingual Abstract)

In agricultural fields, the entomopathogenic fungal species have been investigated for their potential as the biological control agents due to their role of natural enemies for insects. Until recent times, most of the studies for these fungi have been based on isolation from insect cadaver or soil. However, these methods, especially isolation from soil, might cause a problem involving differential isolation of the each entomopathogenic fungi. The purpose of this study is to determine the optimal isolation medium for entomopathogenic fungi using dodine, chitin, and skim milk. The growth rates of entomopathogenic fungi and non-entomopathogenic fungi were compared on dodine agar medium. The medium for this experiment was modified Veen semiselective medium which consisted of based on SDA (Sabouraund Dextrose Agar), 100 mg/ml for chloramphenicol, 50 mg/ml for streptomycin and adjusted dodine to 40, 50, 70 and 100 mg/ml. As a result, optimal concentration of dodine for isolation of entomopathogenic fungi was 50 mg/ml and 168 positive entomopathogenic fungi were isolated in 470 soil samples and 11 cadavers of insect. In addition, the isolates had significantly greater chitinase and protease activity than non-entomopathogenic fungi. The isolation method described represents a valuable tool for rapid and simple isolation of entomopathogenic fungi. These positive entomopathogenic fungi may have potential against variety pests in agriculture.