The relationship of some associated fungi with cold-hardiness of the mountain pine beetle, Dendroctonus ponderosae Hopk.

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dc.contributor.authorStrongman, Douglas Blairen_US
dc.date.accessioned2024-08-15T18:26:09Z
dc.date.available2024-08-15T18:26:09Z
dc.date.copyright1982en_US
dc.date.issued1982
dc.degree.departmentDepartment of Biology
dc.degree.levelMaster of Science M.Sc.en
dc.description.abstractThe relationship between six fungi associated with the bark beetle, Dendroctonus ponderosae HOPK., in lodgepole pine from Riske Cr., B.C. was investigated with emphasis on cold-hardiness. A new technique was developed by which third and fourth instar larvae were reared from fourth stage eggs on host phloem and sapwood blocks colonized by a specific fungus. A control group fed exclusively on sterile phloem. Two blue stain fungi, Ceratocystis montia and Europhium clavigerum: two yeasts , Pichia sp. and Hansenula sp.; and an unidentified basidiomycete; the most common fungi; and a deuteromycete, Trichoderma sp. commonly observed in failing broods were selected for study. Beetles were also reared microbe-free (axenic) from egg to adult on an autoclaved diet consisting of ground phloem, water, and brewers' yeast. In another rearing treatment, eggs and larvae in pine bolts were force-reared in the shadehouse to late instar larvae, teneral and adult. Insects from these rearing treatments were subjected to the following acclimation procedure: l and 2 weeks at +10°C, then 2 weeks at each temperature: +5°, 0°, -9°, -18° and -26°C. For insects from each rearing treatment acclimated to each temperature from +5° to -26 °C, the developmental stage reached, a survival water content, dry estimate, weight, average sugar supercooling point, and sugar alcohol concentration was recorded. Similar variables were measured on wild larvae and beetles collected from the study area in July, October, February and May, 1981-82. Larval development on blocks colonized by E. clavigerum and the basidiomycete was more successful and faster than development on uncolonized blocks. Development in the presence of C. montia, Pichia sp., and Hansenula sp. was poorer than on uncolonized blocks. Trichoderma sp. was antagonistic to beetle development. Least cold-hardy larvae were produced on fungus-colonized blocks and controls followed by axenics then force-reared with wild larvae most cold-hardy.en_US
dc.format.extent91 pages
dc.identifier.urihttps://hdl.handle.net/1828/19818
dc.rightsAvailable to the World Wide Weben_US
dc.titleThe relationship of some associated fungi with cold-hardiness of the mountain pine beetle, Dendroctonus ponderosae Hopk.en_US
dc.typeThesisen_US

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