Identification and biological and physiological characteristics of 3 fungus strains associated with Ips subelongatus.
Three fungal strains associated with Ips subelongatus were isolated from the blue-stain tissue, inside and surface of the body of Ips subelongatus. The fungal stains can cause wood sapstains which associate with the bark beetle attacks. According to culture and morphology characteristic, cycloheximide tolerance and rDNA ITS molecular sequence, the three strains were identified as Ceratocystis fujiensis M. J. Wingf. which is a new record species in China. The optimum conditions for strains growth were as follows: temperature was at 25°C, in complete dark, with pH value 5.0, medium was PDA plus larch phloem extract, supplemented with carbon source of sucrose and nitrogen source of yeast. The three strains had strong tolerance to high and low temperature, so the strains were able to adapt to the larger temperature scale in the north. Dark and acidic conditions in trees were suitable for the growth of strains. C. fujiensis was highly selective to host larch nutrition, and the strains could utilize many kinds of carbon source, but preferred organic nitrogen source.