The efficacy of a new virulent Metarhizium anisopliae variety (M. anisopliae var. dcjhyium, DQ288247) obtained from Odontotermes formosanus in China was evaluated against the subterranean termite, O. formosanus, in the laboratory. The new variety was compared with four other virulent M. anisopliae isolates and was found to be highly infectious and virulent against termites. M. anisopliae var. dcjhyium could cause approximately 100% mortality of termites 3 days post-inoculation in the concentration of 3 x 10(8) conidia/ml. There were also differences in relative hyhal growth and isoenzymes. M. anisopliae var. dcjhyium showed a different isoenzyme band pattern from the four isolates of M. anisopliae (AB027337, AB099510, AB099941 and AF280631). The phytogenetic tree of the 18S rDNA sequences revealed the taxonomic and evolutionary position of M. anisopliae var. dcjhyium. M. anisopliae var. dcjhyium and four isolates of M. anisopliae formed a monophyletic group, supported by a 99% bootstrap value. M. anisopliae var. dcjhyium formed a distinct variety, which had a special characterization of unique bands of isoenzyme, high virulence and tow repellency against termites when compared with four other isolates of M. anisopliae. (c) 2006 Elsevier GmbH. All rights reserved.