Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1982. / Vita. Abstract. Includes bibliographical references (leaves 76-85). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University. / Vita. Abstract. Includes bibliographical references (leaves 46-51). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1987. / Vita. Abstract. Includes bibliographical references (leaves 42-47). Also available via the Internet.

A North American biotype of the old house borer, Hylotrupes bajulus (L.) was established from field and laboratory data. This biotype is based on differences in size and longevity of the life stages and on adult fecundity. N. A. females were observed to oviposit a mean of 165.1 ± 15.5 eggs in comparison to 119.4 (South African) and 105.2 (European). Oviposition period was 5.2 ± 0.5 days for the N. A. biotype and 3.9 and 12 days for the South African and European, respectively. Eggs of the N. A. biotype were smaller than those of the South African and incubation period (8.5 ± 0.3) shorter than both South African (14.0) and European (9-12). Development and comparisons of the pupal and larval stages are presented and discussed. Comparisons of the N. A. and European biotypes under similar temperature, humidity and nutritional conditions found no significant differences between biotypes. These results indicate that the biotypes have undergone little genetic change since their separation over 200 years ago. The old house borer is quite responsive to environmental conditions and the biological variation noted in field populations is attributed to non-genetic modifications of the phenotype. The high degree of biological flexibility noted in this species allows the OHB to inhabit marginal habitats and explains its present world-wide distribution. The OHB was successfully reared from egg to adult in 9-11 months on an artificial diet. An oligidic diet was developed and was composed of ground host tissue (southern yellow pine, Pinus spp.), purified cellulose, agar, and basic nutrients. This diet provided an adequate physical and nutritional environment as noted in the reduction in larval mortality and developmental period when compared to conventional rearing methods. Comparative nutritional, physiological and behavioral studies are now possible between larvae feeding on artificial diets and conventional wooden blocks. Observations of the adult mating behavior, fecundity, oviposition period and egg viability were reported under two mating regimes: single and multiple. Fecundity and egg viability were not significantly different between regimes. However, the number of egg batches, length of oviposition period and the longevity of adult females were significantly different. Adult behavior between regimes was not noticeably different. Males actively compete for females when other males are present and aggressive interactions are common. The practical and evolutionary significance of single and multiple matings is discussed. Consumption, growth, utilization and respiration by three weight classes of old house borer larvae, under 5 constant temperatures and relative humidity were studied. Wood consumption in all larval weight classes was greatest in the temperature range of 20° to 30°C and significantly reduced below and above these temperatures. Growth rates for small larvae were not significantly different among temperatures. Medium and large larvae recorded negative growth rates at 15° and 35°C. Wood utilization was greatest at temperatures of 20° and 25°C. Respiration rates were highest for small larvae. Small larvae were apparently more efficient at converting wood ingested to biomass at all temperatures. / Ph. D.

The significant results of this research were: 1) A laboratory colony of H. bajulus was established and information on the N. A. biotype was collected. At this time it is too early to make any significant statements of comparison between European and N. A. biotypes. However, preliminary results indicate that the mean number of eggs per female, and the size and longevity of N. A. adults appear different than European beetles; 2) Outdoor survival studies of the larvae indicate that H. bajulus can live under natural conditions in Virginia's varied climatic regions. Over the course of two years 27 adults have been collected in such field conditions as fence posts, outhouses, screen windows, building exteriors, and free flying in open fields. This information, along with survival studies, strongly suggest the presence of natural populations; 3) The environment in which H bajulus larvae are located greatly affects its chances of survival. Larvae in attics can survive the fluctuating environmental condition, but growth and development are prolonged and potential structural damage minimal. Under these conditions H. bajulus larvae are more likely to undergo natural mortality over several years. In optimum (stable) conditions H. bajulus will increase their feeding and development. Under these conditions infestations that are left unchecked may lead to serious structural damage and reinfestations. / Master of Science

The formulation of Dursban®, manufactured by Dow Chemical Corp., and its diluting agent were found to influence the penetration abilities of the final spray when it is applied to pine sapwood. The diluent of choice for providing the best penetration of the active ingredient, chlorpyrifos, is an Oil-based carrier for the formulated product Dursban® WT. Dursban® TC, another product containing chlorpyrifos, will penetrate the wood surface better when diluted with water, not with an oil-based carrier such as kerosene. Residual amounts of Dursban® TC applied to pine sapwood will remain relatively constant six months after the initial treatment at depths of 400 - 600 microns below the surface. The wood moisture content (WMC) of treated pine sapwood did not significantly influence the penetration abilities of Dursban® TC at 7.5% - 8.0% and 14.5% - 16.0% WMC. A 1.0% water-diluted formulation of Dursban® TC applied to pine sapwood is predicted to be capable of penetrating the treated wood to a depth of 1320 microns. / Master of Science