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D.Sc. (Zoology) / The influence of some natural enemies and pesticides was studied on Tetranychus cinnabarinus (Boisduval), T. lombardinii Baker & Pritchard and T. ludeni Zacher (Acari: Tetranychidae). Two important predators were discovered, viz: Pardosa crassipalpis (Purcell) (Arachnida: Araneida) and Labidura riparia (Insecta: Dermaptera). Both are more susceptible to some acaricides, especially dimethoate, than the mites. It is proved that the injudicious use of these acaricides, also of DDT and carbaryl, can cause an outbreak of these mites. As to the biologies of the species, the appearance was noted of a fourth chrysalis stage during the development of three T. cinnabarinus females.

Liquid phase catalytic hydrodechlorinations can provide a convenient and environmentally friendly method for treating organic chlorinated compounds in waste streams generated during the manufacturing of agrochemicals. During such treatment hydrochloric acid is generated as a by-product, which can be easily neutralized employing a base to yield an inorganic salt. This work describes the results obtained during the liquid phase hydrodechlorination of 2,6-dichlorophenol (2,6-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP). The hydrodechlorination of these chlorinated phenolic compounds in a mixture of methanol and water was investigated using supported and unsupported palladium catalysts to yield lower chlorinated phenols or phenol. Various parameters were investigated such as catalyst concentration, ammonium formate concentration, effect of base addition and effect of temperature. During this study two methods of hydrodechlorination were also investigated such as hydride-transfer hydrogenolysis, using ammonium formate, and hydrogenolysis, using dihydrogen. These methods offer a mild treatment in terms of the reaction temperature with temperatures used below 800C. A comparison of the palladium catalyst systems using these methods also showed that Pd/C produced the best results in terms of the hydrodechlorination rate and the selectivity towards phenol. When the ammonium formate method was used, complete hydrodechlorination of both substrates was achieved in 1h of reaction time at a selectivity of 100 percent towards phenol. A comparison of the method using dihydrogen and Pd/C showed that the reaction rate and the selectivity towards phenol during the hydrodechlorination of 2,6-DCP were 87.92 percent and 93.30 percent. Similarly, the reaction rate and selectivity during 2,4,6- TCP hydrodechlorination were 63.77 percent and 70.57 percent. These results were achieved in a reaction time of 3 hours. A high catalyst loading increases the reaction rate at the expense of selectivity, due to the formation of cyclohexanone, formed during further hydrogenation of phenol. The formation of cyclohexanone was limited at high temperatures (ca. 800C) with none detected during the hydrodechlorination of 2,6-DCP and 0.19 percent during the hydrodechlorination of 2,4,6-TCP. Evaluation of the hydrodechlorination parameters showed that the catalytic efficiency of the Pd/C catalysts was inhibited as the reaction proceeded due to the formation of HCl as by-product. A significant increase in the reaction rate was achieved when the reaction was performed in the presence of an inorganic base, which neutralized HCl.

"November 2004" / Bibliography: leaves 149-179. / xxviii, 218 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / "This study addresses exposure during spraying of malathion and fenthion insecticides for fruit fly control and hexamethylene di-isocyanate (HDI)-based paint in the automotive and furniture industries. The research aims to characterize exposures and symptoms, and assess the adequacy of personal protective equipment under field conditions." --p. iii. / Thesis (Ph.D.)--University of Adelaide, Faculty of Health Sciences, Dept. of Public Health, 2005

Bees provide important pollination services for crops and wild flowers, estimated to be valued at £120 billion to the global economy. However, declining bee populations have put these services in jeopardy. Pesticides are widely blamed, at least in part, for declines in both wild and managed bee species. Bees are exposed to dietary residues of pesticides when foraging on the nectar and pollen of treated bee-attractive crops. However, these residues are generally found at such low levels that it would not be feasible for a bee to ingest an acute lethal dose. Pesticides which exhibit time-reinforced toxicity could cause mortality to bees over an extended exposure period, though, as the damage they cause can increase exponentially over time. Currently, there is no test for time-reinforced toxicity included in bee risk assessments of pesticides. The overall aims of this thesis were to identify pesticides that exhibit time-reinforced toxicity and determine their effects on a range of demographically important sublethal endpoints in bees. Using a bioassay based on Haber’s Law, I identified fipronil as a pesticide exhibiting time-reinforced toxicity (TRT) in both the honey bee (Apis mellifera) and bumble bee (Bombus terrestris), from four widely-used candidate pesticides. Fipronil at field-relevant levels was found to significantly reduce the longevity and feeding of individual worker bumble bees and those in microcolonies. This nutrient limitation was postulated to be the cause of reduced fecundity of bumble bee microcolonies exposed to dietary fipronil at concentrations of 1 part per billion and less. The toxic effect of fipronil was dramatically increased when microcolonies were placed outside to forage for food, an effect documented by several other studies, and potentially due to an increase in metabolic rate from the need to fly. However, these effects were not observed in queenright Bombus terrestris colonies in the field. This disparity in effects may have been due to problems with exposure to fipronil rather than any possible resilience of colonies. The thesis findings highlight the need for time-reinforced toxicity testing in bees to be integrated into current risk assessment protocols for pesticides. My work in this thesis has provided validation for the use of the TRT bioassay in future risk assessments of pesticides. Current-use pesticides that exhibit TRT, in this case fipronil, pose a serious threat to both wild and managed bees, impacting on demographically important endpoints including feeding and reproduction. Further research, continuing on from the work in this thesis, is needed to ascertain the impacts of TRT pesticides at both colony and population levels. Determining the mechanisms of TRT pesticides will also be key to protecting bees from the danger they pose.

M.Sc. (Zoology) / Please refer to full text to view abstract

A study was made of 801 middle and upper-middle income class urban dwellers, 600 from Richmond and 201 from Roanoke Virginia, to determine the level of their knowledge of and attitude toward chemical pesticides. Certain profile characteristics were delineated and accessed for their relationship to the benchmark data. This sub-study was designed from data obtained from the primary study, "The Effect of a Planned Communication Program on Changes of Attitude and Knowledge of the Urban Dweller Toward Chemicals and Pesticides," Budget Bureau No. 40-6673, Dr. R. H. Gruenhagen, Project Leader. The sample audience scored approximately 70 per cent on the general knowledge questions and approximately 30 per cent on questions pertaining to knowledge of government regulations. This trend followed an evaluation of levels of attitude where general attitude was more favorable than attitude toward government regulations of pesticides and their use. The mean educational level for the population was 12.5 years; mean age was 49. 7 years; three-fifths of the urban dwellers spent their early childhood in metropolitan areas and one-third were members of selected organizations. The majority of urban dwellers participated in certain special interest activities. Urban dwellers from Richmond had a significantly higher level of education than urban dwellers from Roanoke. However, there was no significant difference between the benchmarks for the two groups of urban dwellers. This sub-study indicates that extension educational programs on pesticides should give added emphasis to information on the role of government in regulating their use. Extension educational programs should be tailored to appeal to the high educational level and broad special interest activities of this urban audience. / M.S.