Four species and 10 isolates of entomogenous fungi were tested for virulence against the Formosan subterranean termite, Coptotermes formosanus Shiraki. Five isolates of Beauveria bassiana (Balsamo) Vuillemin and three of Metarhizium anisopliae (Metschnikoff) Sorokin were virulent to C. formosanus. The isolates of these two fungal species were chosen because they originated from different phylogenetic groups of host insects. The B. bassiana isolates originated from hosts in the Orthoptera, Lepidoptera, Homoptera, Dermaptera, and Isoptera; the M. anisopliae isolates came from hosts in the Coleoptera, Isoptera, and Homoptera. The B. bassiana isolate from an isopteran was most virulent to C. formosanus, when LD50 and mean time until death were both considered. There was no other pattern in virulence of isolates relative to the phylogeny of their original insect hosts. All five B. bassiana isolates and one of the three M. anisopliae isolates produced full growth of external mycelium and conidia on the dead termites. Termites exposed to fungal doses killing > 67% of the insects died more quickly than those exposed to doses killing < 67%. Metarhizium flavoviride Gams and Rozsypal was pathogenic to C. formosanus but had low virulence (1% infection in bioassays). Termites that walked across a hyphal mat of Conidiobolus coronatus (Constantin) Batko suffered 100% mortality within 2d, but this fungus did not produce conidia in culture on media.
The influence of dietary sources on the biological changes of a subterranean termite, Coptotermes formosanus Shiraki
