Thesis (Ph. D.)--Virginia Polytechnic Institute, 1966. / Vita. Abstract. Includes bibliographical references (leaves 288-293). Also available via the Internet.

Thesis (M.S.)--Oregon State University, 2001. / Typescript (photocopy). Includes bibliographical references (leaves 45-48). Also available on the World Wide Web.

This study was designed to investigate the repellent effects of pineoil on the Sitka spruce weevil (=white pine weevil), Pissodes strobi Peck, and to evaluate the utility of large scale color aerial photography for detecting weevil attacked Sitka spruce, Picea sitchensis (Bong.) Carr.. Two formulations of pineoil, BBR1 and BBR2, were field tested for their effect in protecting immature Sitka spruce from weevil attack in 36 twenty meter square plots at two locations on Vancouver Island. The pineoil formulations were applied both topically to the terminal leaders and in slow release devices hung at the apical whorl of Sitka spruce trees. The topical application of BBR1 to the leaders of all trees in the plots reduced the number of new weevil attacks to two trees compared with 24 new attacks in the control plots. None of the other pineoil treatments were found to differ significantly from the controls. An examination of the weevil attack history in the study plots showed that the average number of new weevil attacks in the pineoil treated plots were proportionately lower than the number of new attacks in the control plots. These findings suggest that applications of BBR1 to the terminal leaders of Sitka spruce trees will protect them from attack by P. strobi. Large scale color infra-red (CIR) and normal color (NC) aerial photograph stereo transparencies were evaluated for their utility in detecting weevil attacks in immature Sitka spruce stands. Four independent interpreters correctly identified an average of 38% more weeviled trees on CIR film than on NC film during a 1 minute test period. More errors were made by the interpreters with CIR film than with NC film. Interpreter errors made with CIR film were mainly due to a lack of ability to discriminate between new weevil attacks and attacks made the previous year. Errors made with NC film were due mainly to misidentifying healthy trees as new weevil attacks. These findings suggest that for the purpose of detecting weevil attacked Sitka spruce trees, CIR aerial photographs would be both faster and more accurate than NC photographs. / Forestry, Faculty of / Graduate

A somatic embryogenic system was created using material from the British Columbia Ministry of Forests and Range’s Sitka Spruce (Picea sitchensis (Bong.) Carr) breeding program for resistance to the white pine weevil (Pissodes strobi Peck.). The goal was to provide a system that could aid in understanding the phenotypic and genotypic variation that exists in these traits. Embryogenic lines were derived from controlled crosses of parental genotypes previously ranked for the abundance of three physical bark traits: sclereid cells, constitutive resin canals and traumatic resin canals. The number of filled seeds per cone from controlled pollinations was low, with a mean of 9.4 ± 6.8 (mean ± SD), compared to open-pollinated material, which had greater than 40 seeds per cone. The mean induction rate (to embryogenic cultures) was 7 %, ranging from 0 % to 56 % by cross. Of 135 genotypes, 88.1 % produced mature embryos. The number of embryos produced varied by culture. Nearly all (44 of 45) genotypes germinated, with a mean germination rate of 80 %. The overall conversion rate of somatic embryos to plants was 5.5 %. A novel method of cryopreservation that used a temperature pretreatment but did not require dimethyl sulfoxide was tested. Embryogenic cultures were recovered from 31 % of genotypes (n = 112). Genotypic and phenotypic variation were observed during each stage of the somatic embryogenic process. This project demonstrated that somatic embryogenesis and cryopreservation can be used to create a system to study phenotypic and genotypic variation in Sitka spruce. / Graduate

Thirteen white pine plots, ranging from 15-26 years of age and one tenth acre in size, were sampled in six counties of southwestern Virginia. The number of trees attacked by the white-pine weevil ranged from 3.5 percent to 98.6 percent with an average of 40.0 percent. The incidence of forking was found to be 4.1 percent of the trees weevi1ed. Enough trees in the dominant and co-dominant crOvffi categories were either free of weevil attacks or only attacked once that 250 to 300 trees are available for final harvest. Most of the weevil attacks occurred between 5 to 12 years of age. Analysis of Covariance for non-weevi1ed terminals and lateral lengths developed the following relationship for three age classes of terminals and laterals. / Master of Science

Ovariole development and termination of diapause in the white pine weevil were studied by dissecting weevils at various intervals throughout the winter. Old-generation adults brought into the laboratory November produced viable eggs within 5 days. New generation adults brought into the laboratory on November 4 produced viable eggs during November. Viable eggs were deposited by other new-generation adults after 10 to 15 day. at room temperature in winter. On each of the 3 collection date studied, new generation adult produced viable eggs without copulating after collection from hibernation indicating that capulation occurs in the fall. There was no evidence of progressive ovariole development throughout the winter. New generation adults which were isolated as soon as they emerged from the shoots and maintained at constant room temperature had poorly developed ovarioles by November 20 and produced no eggs. Weevil flight and dispersal through a white pine plantation was studied by releasing 409 marked weevils at a central point within a l431-tree plantation and checking every tree at 5-day intervals. Weevils flew readily at the time of re1ease. Marked weevils were recorded throughout the plantation. which extended as far as 330 feet from the release point. A few weevils were observed on scattered white pines 200-300 yards from the release point beyond a hardwood barrier. Total numbers of weevils present on the leaders increased from April 26 to May 5, after which numbers steadily decreased. By June 15, only 20 weevils were observed on the leaders. / Ph. D.