Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Other
Publication Acceptance Date: 6/1/2004
Publication Date: 8/1/2004
Citation: Meikle, W.G., Mercadier, G., Kirk, A., Derouané, F., Rosengaus, R.B., He, Y. 2004. Laboratory bioassays of paecilomyces fumosoroseus on coptotermes formosanus: the effects of termite separation and spore concentrations on termite survival. Society for Invertebrate Pathology Annual Meeting.
Technical Abstract: As part of a larger USDA-ARS project on the management of Formosan subterranean termites, Coptotermes formosanus, exploration for natural enemies of termites, either parasitoids or pathogens, was conducted in six countries by a team from the European Biological Control Laboratory. A total of 99 isolates were obtained, including an isolate of Paecilomyces fumosoroseus from C. formosanus collected in southern China, that was selected for further study. Using C. formosanus shipped from China, experiments were conducted to 1) quantify the density of spores recovered from a termite after treatment in a Potter tower using aqueous suspensions of different P. fumosoroseus conidial concentrations; and 2) compare the treatment of termites with the P. fumosoroseus isolate to a commercial American fungal strain of Metarhizium anisopliae (BioBlast®). With respect to experiment 1), analysis showed that termites treated at 5x106 spores per ml had, received on average between 73 and 116 spores each, while at 5x107 spores per ml the termites received on average between 600 and 733 spores each. With respect to experiment 2), the fungi were compared with respect to their effects on the median survivorship of C. formosanus in petri dishes kept either alone or with other treated termites. Among termites in the control treatments (treated with a blank suspension), termites kept alone had significantly lower survivorship than those kept in groups. In pairwise comparisons of the two fungi at different concentrations, it was found that treatment with the M. anisopliae strain caused significantly lower survivorship among termites kept alone than did the P. fumosoroseus at both 5x105 and 5x106 spores per ml, but the P. fumosoroseus isolate caused significantly lower survivorship among grouped termites, at the same spore concentrations, than did M. anisopliae. These results suggest that there may be desirable characteristics present in pathogens obtained directly from target pests, such as termites, that recommend them as candidate agents for biopesticides.