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24 J. A. Shemanchuk. H. C. Wisler and S. L. Zebold
Field Trials
Recommendations
Literature Cited
(Meigen), and A. flavescens (Muller) were exposed to zygotes of Coelomomyces
psorophorae, but, despite repeated attempts, infections by this strain were never
attained. C. inornata larvae in the same experiment were infected (Zebold et al. 1979).
These results seemed to support the prevailing opinion that Coelomomyces is a
highly specific parasite. In further tests, however, infection was achieved in Culex
pipiens L., C. quinquefasciatus Say, A. aegypti (L.), A. sierrensis (Ludlow), A.
triseriatus (Say), and C. inornata (Louisiana strain).
A. aegypti larvae were more susceptible than the other species, but maximum
resistant sporangia production was consistently best in the original host species, C.
inornata.
In 1979, a preliminary field trial was conducted at 8-Mile Lake near Lethbridge using
laboratory-cultured Coelomomyces psorophorae. Six artificial pools were established.
One pool was inoculated with zoospores and copepods, one received copepods that
were infected in the laboratory and were ready to release the zygotes, two pools
received zygotes from laboratory-infected copepods, and two pools that received no
fungal inoculum served as controls. Into each of the pools, first instar laboratoryreared
larvae of C. inornata were introduced and exposed for 24 hours after which
they were brought back to the laboratory for rearing to final instar and for observation
for infection.
The results from this test confirmed our field observation that the fungus is an
effective killer of C. inomata larvae. The fungus was most effective when introduced
into mosquito habitats in the zygote stage and produced a 64% kill.
These results further indicate that this fungus will have practical application in
controlling C. inornata as a short-term microbial pesticide and as a long-term inoculum
in mosquito-breeding habitats where the fungus does not occur naturally.
(1) Expand research on the design and development of techniques for large-scale
production and long-term storage of Coelomomyces psorophorae.
(2) Evaluate Coelomomyces psorophorae as a short-term microbial pesticide and as a
long-term inoculum in mosquito-breeding habitats in the irrigated areas and in areas
where the fungus does not occur.
(3) Continue searching for Coelomomyces infections in other species of mosquitoes
and define their life-cycles.
(4) Search for other aquatic fungi that might be domesticated and manipulated for the
control of mosquitoes.
Morgante. 0.; Shemanchuk. J.A. (1967) Virus of California Encephalitis Complex; isolation from Cuiisela inornata. Science 157. 692-693.
Shemanchuk. J.A.; Morgante. O. (1967) Isolation of Western Encephalitis virus from mosquitoes in Albena. Canadian JoumJll of
Microbiology 14.1-5.
Whisler. H.C.; Zebold; S.L.; Shemanchuk. J.A. (1974) Alternate host for mosquito parasitic Coelomomyces. Nature 251. 715-716.
Whisler. H.C.; Zebold. S.L.; Shemanchuk. J.A. (1975) Life history of Coelomomyces psorophorae. Proceedings of the National Academy
of Sciences 72. 693-696.
Zcbold. S.L.; Whisler H.C.; Shemanchuk. J.A.; Travland. L.B. (1979) Host specilicity and penetration in mosquito pathogen Coe/omomyces
psorophorae. Canadian Journal of Botany 57. 2766-2nO.