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

No description available.

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

The pine weevil (Hylobius abietis L.) is one of the two topmost economically important insect pests in Swedish conifer forests. The damage increase in areas were the silvicultural practice is to use clear cuttings were the insects gather and breed. During egglaying the female protects her offspring by creating a cave in roots and stumps were she puts her egg and covers it with frass, a mixture of weevil feces and chewed bark. Adult pine weevils have been observed to feed on the other side of the egg laying site and antifeedant substance has been discovered in the feces of the pine weevil. We think it is possible that microorganisms present in the frass contribute with antifeedant/repellent substances. Little is known about the pine weevils associated bacteria community and their symbiotic functions. In this thesis the bacterial community is characterized in gut and frass both from pine weevils in different populations across Europe as well as after a 28 day long diet regime on Scots pine, silver birch or bilberry. Volatile substances produced by isolated bacteria as well as from a consortium of microorganisms were collected with solid phase micro extraction (SPME) and analyzed with GC-MS. The main volatiles were tested against pine weevils using a two-choice test. Wolbachia, Rahnella aquatilis, Serratia and Pseudomonas syringae was commonly associated with the pine weevil. 2-Methoxyphenol, 2-phenylethanol, 3-methyl-1-butanol were found in the headspace from Rahnella aquatilis when grown in substrate containing pine bark. 2-Methoxyphenol and 3-methyl-1-butanol, phenol and methyl salicylate were found in pine feces. Birch and bilberry feces emitted mainly linalool oxides and bilberry emitted also small amounts of 2-phenylethanol. A second part of the thesis discusses the role of fungi in forest insect interactions and the production of oxygenated monoterpenes as possible antifeedants. Spruce bark beetles (Ips typhographus L.) aggregate with the help of pheromones and with collected forces they kill weakened adult trees as a result of associated fungi growth and larval development. A fungi associated with the bark beetle, Grosmannia europhoides, was shown to produce de novo 2-methyl-3-buten-2-ol, the major component of the spruce bark beetle aggregation pheromone. Chemical defense responses against Endoconidiophora polonica and Heterobasidion parviporum were investigated using four clones of Norway spruce with different susceptibility to Heterobasidion sp. Clone specific differences were found in induced mono-, sesqui and diterpenes. A number of oxygenated monoterpenes which are known antifeedants for the pine weevil were produced in the infested areas. / <p>QC 20160601</p>

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.

Abstract This thesis is a study of the odour responses of insect olfactory (or odorant) receptor neurons (ORN) of blowfly (Calliphora vicina), mosquito (Aedes communis), fruitflies (Drosophila melanogaster and D. virilis) and large pine weevil (Hylobius abietis). A power-law dependence (similar to Stevens' law in psychophysics) was obtained for the action potential rate of ORN responses vs. odour concentration in measurements with metal microelectrodes from blowfly ORNs and an analysis system was developed for the extracellularily recorded action potentials (or nerve pulses). Odour exposure sequences were used to study action potential rates quantitatively as a function of odour concentration in air exposure. For an odour exposure sequence, a known initial amount of the odour compound in a filter paper inside a Pasteur pipette at the beginning of repeated exposures caused a gradual dilution of the odour concentration in the exposure sequence. The concentration at each exposure was calculated according to the discrete multiple headspace extraction and dilution (DMHED) method. The estimated odour concentration was assumed to obey in the method an exponential law with respect to the exposure number in the sequence. Despite that many uncontrollable parameters remain for measuring quantitatively the characteristics of the ORNs, the results obtained, e.g., sensitivity, specificity, adaptability, and the power-law realation are both biologically and technically very interesting. A time-to-voltage converter (TVC) was utilized for the response analysis in determining action potential intervals originating from a single ORN. A precision analysis of TVC was also performed. With the mosquito (Aedes communis), fruitflies (Drosophila melanogaster and D. virilis) and large pine weevil (Hylobius abietis) antennae were tested for inhibitory and excitatory effects to find out repellents and attractants. Human sweat was found to cause strong stimulus exposure in the responses of the mosquito ORNs and Neutroil® caused inhibitory responses in pine weevil ORNs, respectively. The power-law exponents for blowfly ORNs were about 0.19 in the case of 1-hexanol (HX), 0.065 in the case of 1,4-diaminobutane (14DAB) and 0.32 in the case of butyric acid (BA). The corresponding Stevens' law exponent values 0.39 and 0.33 have been reported for HX and BA, respectively, by Patte et al. (1975).

The large pine weevil, Hylobius abietis L., is a major insect pest on conifer seedlings in northern Europe. Due to its feeding newly planted trees get girdled, resulting in high seedling mortality (up to 80%). As a consequence great financial losses to the forest industry occur. Today the seedlings are protected with the pyrethroid insecticide cypermethrin. This insecticide is toxic to aquatic organisms and is, from 2010, prohibited for use in Sweden by the Swedish Chemicals Inspectorate. An alternative to insecticides is to protect the seedlings with antifeedants, compounds that, either through taste or smell or both, deter the weevils from feeding. This thesis describes the search for and the synthesis of such antifeedant compounds. Bark extracts of several woody species, known to be non-palatable to the weevil, were prepared and found to display antifeedant activity against H. abietis. The major chemical constituents of the extracts were tested for antifeedant activity. Antifeedants such as eugenol, 2-phenylethanol and benzylalcohol, but also feeding stimulants such as β-sitosterol and linoleic acid, were identified. An extract of linden bark, Tilia cordata, was shown to contain nonanoic acid, a highly active antifeedant. Other aliphatic carboxylic acids were also found to display high antifeedant activities against the weevil, both in laboratory and in field tests. The enantiomers of dihydropinidine, a piperidine alkaloid present in several conifer species, were prepared by dimethylzinc mediated allylation of 2- methyltetrahydropyridine-N-oxide. When tested in micro feeding assays, no difference in antifeedant activity was found for the enantiomers. In a field test high antifeedant activity, comparable with that of the presently used insecticide cypermethrin, was found for (±)-dihydropindine. Other naturally occurring piperidine alkaloids were synthesised and also found to display high antifeedant activities in laboratory tests. Structure-activity relationships were evaluated for methoxy substituted benzaldehydes, benzoic acids and cinnamic aldehydes, -acids, -esters and -alcohols. While the carboxylic acids were inactive or even feeding stimulants, the aldehydes were the most active antifeedants / QC 20110124