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Tolypocladium cylindrosporum GAMS isolated from Aedes australis ERtCHSONin New Zealand, and another strain isolated from soil in Czechoslovakia have shown pathogenicity for larvae of mosquitoes. The infection was transmited with conidia suspended in water and hyphae entered the body of larvae from the midgut. First symptoms of the infection appear 5 days after infection ; in 7 days all exposed larvae were killed. Pupae and adult mosquitoes were not infected. Both strains grow and sporulate well on Sabouraud's agar. Somme morphological data show the variability of hyphae, conidiophores and conidia.During ecological studies of Aedes australis ERICHSON in the area of Quoin Point (30 miles South of Dunedin, Otago Cost of New Zealand) a fungus was recorded in 1969 infecting larvae and causing mortality during the winter period. The fungus was isolated on Sabouraud's medium and compared with other Deuteromycetes infecting mosquitoes.It differed in some morphological details from Culicinomyces clavosporus described by COUCH, ROMNEY & RAO in 1974 from similar infections of mosquitoes. When submited (Oct. 1979) for taxonomic study to Dr O. FASSATIOVA, Curator, Deuteromycete collection, Inst. of Botany, Charles University, Prague, she determined the fungus as belonging to Tolypocladium cylindrosporum GAMS, a saprophytic aquatic or terrestrial fungus, described by GAMS in 1971 from soil samples. Under its proper identification the New Zealand strain has been studied together with a culture from a series of isolates which were the basis for GAMS'S description of Tolypocladium cylindrosporum and which was collected in Czechoslovakia. MATERIAL AND METHODSThe New Zealand strain was collected with infected mosquito larvae with sign of outside growth of white hyphae. The larvae were surface sterilized in 2 % formalin and deposited on Sabouraud's agar slants, and the fungus colony was cultivated at 25 ~ C for 2 weeks. Conidia on the surface of the colony were collected with a sterile platin loop and transferred to a new medium for cleaning the colony from bacterial contamination. The clean fungus was maintained as isolate on fresh Sabouraud agar slants in the collection of the Institute of Microbiology, Dunedin. For experimentation, medium in Petri dishes was inoculated with conidia and after 14 days at 25 ~ C the conidia were scratched off with a lancet and brushed off in sterile vials. Conidia were used for dusting on the surface of the test-cup with mosquitoes or in a very dense water suspension for adding of measured volumes to a known volum of water. The concentration of conidia was counted in a hemocytometer.

The New Zealand strain of Tolypocladium cylindrosporum was cultured on Sabouraud dextrose agar medium under varying regimes of growth conditions. The isolate exhibited good tolerances to temperature (4-35 degrees C), pH (3-10) and salinity (0-7% NaCl). Optimal vegetative growth and sporulation were recorded between a temperature range of 20-30 degrees C, pH of 5-6 and a salinity level of 0-2% NaCl. The North American isolate of the fungus showed similar tolerances, while the European isolate was less tolerant.

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