The synthesis of p-menthane-3,8-diol via the acid-catalyzed cyclization of citronellal in a dilute aqueous sulphuric acid medium was investigated using conventional batch and continuous systems in order to develop a commercial production process for said p-menthane-3,8-diol (PMD). The batch studies conducted during the first part of this study showed that the formation of PMD from citronellal occurs via an intra-molecular Prins reaction that results in the formation of both the desired PMD product, as well as the partially hydrated isopulegol. It was shown that the formationof the by- product, PMD-acetal, results from the reaction between an intermediate, 5-methyl-2- isopropylcyclohexanol, and the citronellal starting material, and not from the reaction between PMD and citronellal as previously reported. Kinetic studies confirmed the existence of a complicated kinetic model. The formation of PMD from citronellal displayed typical pseudo first order kinetics up to conversions of 70 after which the kinetic model becomes complicated as the result of the establishment of quasi equilibrium reactions between PMD and isopulegol (dehydration of PMD and hydration of isopulegol) and between PMD the PMD-acetal, both systems being acid catalysed. The PMD-acetal formation reaction appears to be second order with respect to PMD. Scale-up studies of the batch process to 30L and 50L scales showed that it would be extremely difficult to limit the level of PMD-acetal formation below the desired level of 1 percent, even if citronellal conversions are restricted to about 50 percent. During studies conducted on a commercially availablemicro-structured organic synthesis plant (OSP) it was shown that it is possible to perform the PMD reaction as a continuous process. The results obtained showed that the use of a micro-mixer such as the caterpillar micro-mixer did not provide enough residence time in order for desirable conversions (- 40 percent) to be obtained. By combining themicro-mixer with delay-loops of different thicknesses and lengths, and using increasing reaction temperatures, it was shown that the conversion of citronellal could be improved to some extent, but compared poorly to the expected conversions for a well-stirred batch reactor. By packing selected delay loops with inert SiC particles, improved mass transfer was observed between the organic and aqueous phases as reflected in the increased conversion of citronellal. Using the observations that were made during the use of the OSP, a continuous-flow, tubular reactor system was designed and constructed. Advanced statistical techniques were used to investigate the effect of variables such as temperature, acid concentration, reactor length, flow rate and the organic to aqueous ratio on the rate and selectivity of the reaction. Mathematical models were derived for citronellal conversion, yield of PMD and yield of PMD- acetals, and used to predict the concentrations of citronellal, PMD and PMD-acetals at set experimental conditions. The results obtained showed that it was possible to obtain a product which approached desired specifications.Downstream processing of the PMD reaction mixture as it exits the reactor requires phase separation and neutralization of the acid catalyst solution, followed by further work-up to recover unreacted starting material and intermediates for recycle back to the synthesis reactor, followed by purification of crude PMD to the desired specification. The study showed that neutralization, prior or after phase separation, does not affect the selectivity of the PMD to such a great extent, but does influence the relative conversion due to extended contact of the catalyst with the organic phase after the reaction is terminated. Recovery of unreacted citronellal and isopulegol could be achieved by a simple vacuum evaporation step, which may either be carried out in a batch manner using traditional distillation equipment, or in a continuous process using wiped-film (short path) techniques. It was also shown that selective crystallization of PMD from the crude product mixture by addition of a solvent, such as heptanes or hexane proved to be the best way of achieving the desired product specification.

White mold caused by Sclerotinia sclerotiorum attacks a wide host range of broad-leafed plants which includes potatoes. Current control is limited to the use of chemicals, but biological control has emerged as an eco-friendly alternative. For the study, 19 bacterial strains and 18 fungal strains obtained from soil samples taken from a potato field naturally infested with the pathogen S. sclerotiorum were tested for the effects on S. sclerotiorum mycelium growth and sclerotia viability in vitro. A total of eight bacterial strains and six fungal strains proved to be effective in the inhibition of S. sclerotiorum mycelium growth on PDA plate using a dual culture technique. These antagonistic microbes were six Bacillus subtilis, Bacillus pumilis, Bacillus marisflavi, Fusarium solani, Fusarium equiseti, Fusarium chlamydosporum, Aspergillus niger, Aspergillus insuetus and Penicillium citrinum. There was a significant difference (p<0.05) in the interaction between S. sclerotiorum mycelium growth and the time after inoculation with a S. sclerotiorum mycelium plug for both bacterial and fungal soil isolates. An additional sclerotia viability test was carried out using four of the eight antagonistic bacteria, and six of the antagonistic fungi. The results showed that two Bacillus species, namely B. pumilis and B. marisflavi can effectively reduce sclerotia viability. The other two bacteria (both B. subtilis), recorded low percentage reduction in sclerotia viability. As for the six antagonistic fungi, the viability test proved to be less effective in determining sclerotia viability. However, the result of this study supports the use of bio-control agents, not only because they are environmentally friendly, but because they are also an effective way of controlling the plant pathogen, S. sclerotiorum.

Three naturally-occurring epizootics of Paeteurella pseudotuberculosis in canaries were studied. Cultural details and gross histopathological lesions were described for birds from two of the aviaries. Epizootiological observations were made in all three cases following visits to the premises and recovery of data on management, first clinical signs, and mortalities. A reasonably complete study was made of early and current literature concerning pseudotuberculosis infections and incidence in birds and mammals, both feral and domesticated. Although this disease has been commonly reported in canaries in Europe from 1884 onwards, the epizootics herein reported are, as far as the author is aware, the first bacteriologically confirmed canary Infections to be reported on the North American Continent. Because of the high mortalities encountered, and because of the known potential of the causative organism to produce human disease, the epizootiological considerations were extended to Include experimental studies on the faecal excretion rate of viable Pasteurella pseudotuberculosis by naturally and artificially Infected canaries. With the evolution of suitable culturing techniques, the recovery of viable organisms of the inoculation strain from experimentally infected canaries was performed with ease. This allowed counts to be carried out on total daily faecal samples from twenty inoculated and four control birds for a three-week period following oral inoculation. It was found that in the group of twenty inoculated birds which suffered five (20%) mortalities, some sixteen (80%), including those birds that died, excreted organisms for periods ranging from three up to nineteen days. Peak amplitudes for the estimated faecal counts of Pasteurella pseudotuberculosis per day varied from Log 4.3 up to Log 8.1. The four dead birds showed gross lesions typical of naturally-occurring pseudotuberculosis, and yielded recovery cultures from various organs. The remaining twelve shedder birds all ceased shedding viable P. pseudotuberculosis by the twentieth day following -the conclusion of oral Inoculations (24th experimental day), and although none yielded a positive culture from various organs, there were slight-to-marked splenic lesions in all but two when they were autopsied on the twenty-fifth experimental day. Four birds which never shed detectable numbers of viable P. pseudotuberculosis were found to have no visible gross lesions when sacrificed and autopsied. Four non-inoculated control birds also failed to shed detectable numbers of viable P. pseudotuberculosis. Attempts were made in the laboratory to allow naturally and experimentally infected canaries to transmit the infection to healthy contact birds. These attempts were unsuccessful, and it was concluded from this and from direct observations on the natural epizootics that predisposing factors other than the presence of the organism (such as climatic or poor-management stress, or gastro-intestlnal irritation) are required at times for the disease to become epizootic in canaries. From the faecal excretion rates of viable pseudotuberouloeis measured in experimentally infected birds, and from epizootiological observations, it was concluded that canaries infect each other (rather than the infection coming from a common source) and that they are potential spreaders of infection (or of the infecting organism) to other species in contact, including man. Gross and histopathological observations of experimentally Infected birds correlated with their faecal counts, and gross pathological observations on naturally-Infected birds, indicate that lesions in the bowel wall, in particular caecal abscesses, are the lesions which when present predispose to a high potential of infectivity in the shed faeces. / Science, Faculty of / Zoology, Department of / Graduate

An analysis was made of the distribution of and interactions between three major species of insects in cones of Douglas fir. This was based on over 3,500 cones from 93 trees in 1961 and 4,000 cones from 97 trees in 1962. High variation in damage was found among trees for each of the three insect species studied (Contarinia oregonensis Foote, Megastigmus spermotrophus Wachtl., and Dioryctria abietella D.&S.) In C. oregonensis this variation was significantly related to the height of the trees and dates when cones became pendent. The percentage of filled seeds and average cone size of the trees were important in M. spermotrophus. The average cone size of the trees and duration of vegetative bud flushing were significantly associated with D. abietella. The within tree-variation of damage by C. oregonensis was highly significant and consistant from tree to tree and year to year. Damage increased significantly from the bottom to the top of live crown. Suggestions are made to help increase the seed yield by chemical control of insects by selection of uninfested or slightly infested trees by sequential sampling, and by selection of cone and seed insect resistant trees for seed orchards. Although no tree was wholly resistant to all three insects the best, with only 4.8 per cent of its seeds damaged, was so much better than average that it may be of considerable economic importance. The great range in apparent resistance of trees to attack by cone and seed insects should be recognized in further studies and attempts be made to determine biologically sound reasons for the observed differences. / Forestry, Faculty of / Graduate

A survey of inspection records of Anjou and Bosc pears shipped to market between November 1, 1956 and March 30, 1957 show storage rots to be an important problem of the Rogue River valley pear industry. Considerably more rot occurred in the Bosc than in the Anjou pears. Tissue isolations from the common blue mold and gray mold rots consistently yielded Penicillium sp. and Botrytis sp. respectively. Isolations showed Cladosporium sp. to be almost always associated with a brown, superficial rot of Anjou and with a brown-black rot of Bosc pears. Packing-house tests of three concentrations of Stop-Mold B showed it to be an effective rot-preventative. An apparent improvement in the control of rots with increased concentration of Stop-Mold B solution occurred in one lot of pears. Another lot showed an apparent decrease in control of rots with increased concentration of this fungicide. Packing-house tests of fungicides for prevention of rots were conducted in 1958 and 1959. Of the nine fungicides tested, Busan 50 was the most effective for rot control but resulted in a severe, brown skin discoloration. The commonly used post-harvest-dip chemical, Stop-Mold B, ranked high in all of the tests and is considered to be the best of the fungicides tested. The high percentage of storage rot spots with a broken surface indicates the importance of handling fruit carefully to avoid injury. Penicillium was the most prevalent rot of the pears examined during these investigations. Next was Cladosporium rot, then Botrytis rot. Cladosporium rot is shown to be a major storage rot of winter pears in the Medford area and is not necessarily associated with skin breaks. / Land and Food Systems, Faculty of / Graduate

The chemical properties of the wood of red alder (Alnus rubra Bong.) were examined after exposure to decay by three organisms, Fomes pinicola (Schwartz ex Fries) Cooke, as a brown rotting fungus, Polyporus versicolor L. ex Fries and Stereum hirsutum Fr. as white rotting fungi. Cold- and hot-water solubility were most affected by all three test fungi. The increase in methanol-benzene solubility and in one-percent sodium hydroxide solubility were the highest in samples decayed by F. pinicola, but the changes were less pronounced than observed for the water solubles. Destruction of cellulose and lignin appeared in samples decayed by P. versicolor. The deterioration of cellulose and lignin by the other two fungi was within the limit of experimental error of the determination methods used. / Forestry, Faculty of / Graduate

The paper describes a Douglas-fir classification for the interior of British Columbia which was developed for the purpose of identifying trees susceptible to the attacks of the Douglas-fir beetle, Dendroctonus pseudotsugae Hopk. The significance of the depredations of the beetle to the objectives of sustained-yield forestry is discussed and the need for control and continuous protection stressed. A method of direct control of bark beetles is exemplified and receives criticism for its laborious-ness, high cost, and temporary protection. It is noted that foresters and entomologists are increasingly cognizant that forest management should strive for insect control through the development and maintenance of forest conditions unfavourable to insects. These conditions become manifest in vigorous forests which possess an inherent resistance to insect attack. By harvesting on a selective and critical basis the forest may be made relatively resistant and insects can be controlled by indirect means. Detailed reference is made to a system of indirect control developed for ponderosa pine forests against the attacks of the western pine beetle, Dendroctonus brevicomis Lec. The theory, development, and application of the system is considered and later referred to in the light of the results of the present study. The possibility of developing similar systems for other insects and hosts is demonstrated from the literature. Similarly, the ability of other workers, to classify Douglas fir into vigour and age groups is shown. In view of the apparent feasibility of judging the susceptibility of classes of Douglas fir to attack by beetles an attempt was made to develop a classification which might have value in this regard. A classification was developed and tabulated from data collected at Westwold, B. C. in the interior Dry Belt at an elevation of 3,000 feet. The method is described in detail and the limits of the four vigour classes and of the four age groups are statistically justified. The classification was tested for its accuracy in judging actual and relative age and vigour at Westwold and also at Lumby in the interior Wet Belt. The results of the tests are tabulated and the reason for the high degree of accuracy in judging actual vigour in terms of diametral growth attributed to the measurements of phloem streaks. Infested trees were objectively classified on an area of eight square miles at Westwold to determine which classes of vigour and age were susceptible to attack. The results reveal that the older, slower growing trees are most susceptible. Specifically, trees of over 150 years of age with a ten-year diametral growth of less than 11 millimetres are most likely to be infested. The type of host selection made by the Douglas-fir beetle is compared to a combined thinning from below and a selection cutting of the older age classes. It is suggested that, in forests subjected to endemic populations of beetles, trees of classes 2D, 3C, 3D, 4C, and 4D be harvested to increase the vigour and resistance of the residual stand and to implement indirect control. / Forestry, Faculty of / Graduate

In the hope of finding male-sterile alfalfa strains for use in the production of hybrid alfalfa, a microscopic study of the pollen produced by approximately 1000 lines of alfalfa grown at the University of British-Columbia was conducted. This study revealed 4 lines that consistently showed an absence of viable pollen under different environments. 2 of the male-sterile lines produced no seed on selfing and 2 produced very small quantities of seed. In plants grown from open-pollinated seed of the 4 male-sterile lines, the F₁ segregation for male-sterile to male-fertile were as follows: 1:7.9, 1:7.3, 1:6.8, and 1:8.3, for an incomplete count. These ratios suggest that the male-sterility is controlled by cytoplasmic factors in addition to recessive genes. However, the mode of inheritance will only be factorially interpreted by F₂ and backcross data. It appears that the sterility is caused by a breakdown in meiosis, as the pollen sacs are full of an amorphous material suggestive of arrested development of the pollen grains. The male-sterility should eventually prove of great economic value in the production of hybrid alfalfa seed. Male-sterility has not previously been isolated in alfalfa, although it is common in the plant kingdom. Over the past 10 years the Witches' Broom virus disease of alfalfa has developed into serious proportions in the Interior of B.C. - this was first pointed out by quadrat results obtained in 1942-44. The disease is known to be distributed throughout the low rainfall areas of the province where it is widespread although sporadic. The disease is shown to be the same disease that occurs in Washington and in Australia. Witches' Broom of Alfalfa causes severe dwarfing of the affected plants and a decimation of alfalfa stands. Drastic shortening of internodes and reduction in size of leaves is accompanied by proliferation of crowns and nodes. Up to 3000 thin spindly shoots are commonly produced by a single diseased crown. Typically, leaves are marginally chlorotic; inflorescences are reduced to 3-4 florets per raceme; and, very little, if any, seed is produced. Crowns and roots are symptomless until late stages of the disease are reached, when they show severe rotting. Affected plants gradually die in a period of 3 months to 2 years. However, 2 plants were shown to apparently recover from the disease when brought into the U.B.C. greenhouse from the Nicola Valley. A histological comparison of the healthy and diseased plants showed gummosis of the xylem vessels, a breakdown and degeneration of the chloropasts of the affected leaves, and a mechanical breakdown of the palisade layer in the outer edge of diseased leaves. Storage of starch in the crowns of plants was found to be depleted according to the stage of the disease, with no storage starch present in severely diseased crowns. However, sucrose was found to be present in storage in diseased crowns but not in healthy crowns. The disease was found to be easily transmitted by crown grafts. Out of 142 attempted grafts, union of scion and stock was achieved in 31 cases with positive transmission in 27 cases. Seed transmission and inoculations by expressed crown juice have given negative results to date. Quadrats were plotted in 1950 in the interior of B.C. to further study the disease. Twinning experiments were set up to study natural resistance of the members of the genus Medicago. Results from both of these studies will not be ready for publication for at least 2 more years. A nursery plot was established at U.B.C. and a replicate plot at Kamloops, B.C. One year after planting the Kamloops plot, several of the alfalfa plants were found producing symptoms of the disease, and to be badly diseased in 15 months time. None of the plants at U.B.C. showed any signs of the disease. From a potted plant yield trial conducted at U.B.C. the diseased plants were shown to have a statistically significant reduction in yields as compared to healthy plants. / Land and Food Systems, Faculty of / Graduate

A disease, causing severe flagging of young western white pine (Pinus monticola Dougl.), was investigated at Hill Siding and Arrow Park, British Columbia. The primary symptom of the disease was flagging of twigs, resulting from a rapid necrosis of terminal shoots and less commonly from girdling-lesions on 2-year-old growth. A small percentage of the severely flagged trees died. Damaging effects of the disease were confined to trees under 40 years of age and to stand forms with a higher than average component of white pine in the susceptible age class. Efforts to isolate the causal fungus yielded 22 fungi in culture, only two of which occurred with sufficient frequency to warrant further study, an unknown fungus "B” and Pullularia pullulans (deBary) Berkhout. A search for fructifications associated with the disease revealed apothecia of a Tympanis, very similar to those of Tympanis pithya (Karst.) Karst., to be associated with 16 per cent of a random sample of 425 flagged twigs. The pycnidia of the imperfect stage of Tympanis sp. occurred less commonly. Spore cultures from Tympanis apothecia were different from those of any of the 22 fungi isolated in tissue culture and it seemed probable that Tympanis occurred as a pioneer saprophyte on killed twigs. External signs of Pullularia pullulans occurred commonly in the form of erumpent sclerotia, and external hyphae with resting spores. A scale insect, resembling Matsucoccus sp., was found at a high infestation level in one stand and less commonly in the remaining stands. Reasons for discounting the insect as a primary causal agent of flagging are outlined. Field inoculations with Pullularia pullulans and greenhouse inoculations with Pullularia pullulans and the unknown fungus "B" produced questionable results with the latter fungus, but indicated Pullularia pullulans to be pathogenic under the conditions imposed by the experiment. Results of inoculation experiments are snmmarized in four tables. The historical background and cultural description of Pullularia pullulans is outlined. Experimental and observational evidence suggests that the fungus is one of the causal agents, and probably the primary agent for the flagging. On the basis of the limited damage caused by the flagging and the sporadic occurrence of the susceptible stand form, control measures are deemed unwarranted. / Forestry, Faculty of / Graduate

A canker on the main stem of oppressed western hemlock (Tsuga hetero hylla (Rafn.) Sarg.), 1 to 3 inches in diameter at breast height, was found at Powell River and Tumour Island, British Columbia. The canker is irregularly elliptical, with a conspicuous resin exudation in the early stages. The canker appears to be annual. A species of Cephalosporium (Fungi Imperfecti, Moniliales) was consistently isolated from cankers collected at Powell River. The pathogenicity of the organism has not been proven to date. The growth and hyphal characters of the organism, and the temperature-growth relations of the organism in culture are described. The conidial apparatus of the organism was investigated. Attempts to produce the perfect stage in culture were unsuccessful. / Science, Faculty of / Botany, Department of / Zoology, Department of / Graduate