pdf, 57.71Mb - Entomological Society of Canada

Literature Cited
C. Application ofmicrospnridia and fungi. 265
The level of research effort on fungi for control of spruce budworm has been low
compared to the effort on such biological agents as the viruses and B.t., but the results
obtained to date suggest that fungi playa significant role in the regulation of spruce
budworm populations, and the recent demonstration that infectious diseases can in
theory drive population cycles (Anderson & May 1980) will provide further impetus for
studies designed to delineate the role of fungi in the spruce budworm ecosystem. To this
end, extensive epizootiological investigations on the biotic and abiotic factors affecting
the fungus-budworm interaction should be carried out. These, coupled with continuing
laboratory studies on the production of fungal material suitable for field dissemination.
and on the selection and mode of action ofthe most virulent strains of fungi. will. in the
long term. determine how and under what circumstances fungi may be used in the
manipulation of spruce budworm populations.
At present it is difficult to draw definite conclusions on the potential of microsporidia
and fungi in the management of the spruce budworm. However. because of their
potential in a control programme. any comprehensive model of spruce budworm population-dynamics
must embrace a thorough understanding of these pathogens.
Research into the genetic manipulation of the spruce budworm to date has supplied
the basic level of information required for further testing: methods for mass sterilization.
effects on fertility of caged population, and dispersal and detection of released insects.
However, the large numbers of insects and extensive areas of forest affected by epidemics
of this pest suggest caution in trying to develop genetic manipulation for control of
outbreak populations. The logistics of application, in terms of numbers and area. and the
uncertainty of success indicate that its greatest potential lies in controlling endemic
population levels, where the released insects' ability to detect and mate with females
even when they are relatively rare provides one of the greatest advantages of the genetic
approach. Future research should be aimed at such low level populations, and should be
conducted with the objective of reducing reproduction potential to a level below that
necessary to support a transition from endemic to epidemic levels.
Anderson. R.M.; May. R.M. (1980) Infectious diseases and population cycles of forest insects. Science 210.658-661.
Burges. H.D. (Ed.) (1981) Microbial control of pests and plant diseases, 1970-1980. London; Academic Press, 949 pp.
Ennis. TJ. (1979a) Detection and isolation of induced chromosome aberrations in Lepidoptera. Experientia 35.1153-1154.
Ennis, T.J. (1979b) A release·recapture experiment with normal and irradiated spruce budworrn males. Cana4ian Forestry Service Bi·
monthly Research Notes 35.9-10.
Harvey. G.T.; Burke. J.M. (1974) Monality of the spruce budworrn on white spruce caused by Entomophthora sphaerosperma. Canadian
Forestry Service Bi·monthly Research Notes 30.23-24.
Kenneth. R.G. (1978) Entomophthora sphoerosperma as an insect pathogen for spruce budworrn control. Abstracts of the Acadian
Entomological Society's 38th AnnWlI Meeting. pp. 35-36.
Lachana:. LE. (1979) Genetic strategies affecting the swx:css and economy of the sterile insect release method. In: Hoy. M.A.; McKelvey. J.J.
(Eds.) Genetics in relation to insect management. Rockefeller Foundation. USA.
Otvos.I.S.; Moody. B.H. (1978) The spruce budworm in Newfoundland: history. status and control. Canadian Foresty Sen·ice. Newfoundland
Forest Research Centre, Information Report N·X-150.
Outram. J. (1969) Potential use of the sterility principle for spruce budworm control in eastern Canada. Canadian Department of Fisheries and
Fort'stry' InteTllal Report M-45. Fredericton. N.B.
Perry. D.; Tyrrell. D. (in prcss) Resting spore germination in ZoophtllOra radicans. Mycologia.
Rctnakaran. A. (1970) Preliminary results of radiation induced sterility of the male spruce budworm. Canadian Department of Fisherit's and
Forestry' Bi·monthly Research Notes 26.13-14.
Retnakaran. A. (1971) Thiotepa as an effective agent for mass sterilizing the spruce budworrn. Choristoneura fumiferana (Lepidoptera:
Tortricidae). Canadian Entomologist \03.1753-1756.
Thomson. H.M. (1958) The effect of a microsporidian parasite on the development. reproduction and mortality of the spruce budworrn.
Choristoneura fumiferana (Clem.). Canadian Journal of Zoology 36.499-51 J.
Tyrrell. D. (1977) Occurrence of protoplasts in the natural life cycle of Entomophthora egressa. Experimental Mycology 1.259-263.
Vandenberg. J.D.; Soper. R.S. (1978) Prevalence of entomophthorales mycoses in populations of the spruce budworm. Choristoneura
fumiferana. Environmental Entomology 7.847-853.