Thesis (M.S.) in Chemistry--University of Maine, 2002. / Includes vita. Bibliography: leaves 102-107.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

4 pp. / DeGomez, T. 2006. Preventing Bark Beetle Attacks on Conifers with Insecticides. University of Arizona, College of Agriculture and Life Sciences Bulletin, AZ1380. Tucson, Arizona. / A common method of protecting individual trees from bark beetle attack in the western U.S. is to saturate the tree bole with carbaryl using a hydraulic sprayer at high pressure. With this type of application method spray deposition will occur off-target and may contact open waters where sensitive species are subject to the toxic effects of the pesticide. We report on a recent study in which the authors reported carbaryl drift resulting from single tree protection treatments poses little threat to adjacent aquatic environments, a primary concern when treating trees in campgrounds in the Western United States. Using reasonable no-spray buffers will ensure that adjacent aquatic environments are protected from any negative impacts.

My study of the effects of carbaryl in aquatic systems under controlled laboratory conditions emphasized four major objectives: (1) to determine the acute toxicity of carbaryl to the herbivorous adult and immature Trichocorixa reticulata (Guerin)(Hemiptera: Corixidae), and to the omnivorous larvae of Glyptotendipes barbipes (Staeger) (Diptera: Chironomidae) under static bioassay; (2) to adapt a quantitative method of analysis for carbaryl in water and whole insect tissue extract; (3) to measure the accumulation of the insecticide by G. barbipes under static exposure; and (4) to quantify the uptake and loss of carbaryl by G. barbipes under daily-renewed sublethal dosages.

Alkaline degradation of Carbaryl in the presence of CTAB micelles has been reported as the most efficient method; however, the factors accounting for it are not yet clear. The main objective of this work was to study some of the factors affecting the alkaline degradation of Carbaryl in the presence of cetyl trimethylammonium bromide (CTAB). Three specific aims were researched in order to address the main objective. Solubility studies, UV-vis, fluorescence, and 1D-HNMR and 2D-HNMR spectroscopies were used to research the solubilization of carbaryl in CTAB micelles. Solubility studies showed that carbaryl partitions into CTAB micelles with a binding constant of 553 ± 8 M-1, and each mole of micellized surfactant incorporates about 0.336 moles of carbaryl. Spectroscopy studies showed that carbaryl does not interact electrostatically with micelles but does through van der Waals interactions. 1D-HNMR and 2D-HNMR indicated solubilization in the Stern layer, oriented with its hydrophilic moiety towards the Goüy-Chapman layer and the hydrophobic moiety towards the core of the micelle. Kinetic studies as a function of the surfactant concentration along with micellar kinetic models were used to calculate micellar rate constants (k’M) for each of four different cationic surfactants: cetyl trimethylammonium hydroxide (CTAOH), cetyl trimethylammonium bromide (CTAB), cetyl trimethylammonium chloride (CTACl), and cetyl pyridinium chloride (CPCl), and compared to the corresponding rate constants (k’W) in water; the results in all cases showed k’M / k’W > 1. This fact led to the conclusion that additional factors beyond solubilization of substrates are playing a role. Solubility studies revealed the following binding constant order and solubilization capacity order: CPCl > CTAOH ≈ CTAB > CTACl, CPCl > CTAOH ≈ CTAC > CTAB, indicating that for CPCl, Coulombic interactions, such as charge-transfer complexes, may be favoring the concentration effects, while for other surfactants, such as CTAOH, the [–OH] as the micelle counterion increases Carbaryl’s concentration in the Stern layer compared to its bulk concentration. In contrast, large, weakly-hydrated polarizable ions such as Br– displace hydrophilic ions, providing less enhancement. Kinetic experiments as a function of the surfactant head’s charge led to the conclusion that cationic and zwitterionic surfactants have a catalytic effect of the alkaline hydrolysis of carbaryl, while nonionic and anionic surfactants have inhibitory effects: kobs (cationic) > kobs (zwitterionic) > kobs(nonionic) > kobs (anionic). A similar order for solubility parameters (Ks and SC) was observed from equilibrium solubility studies. Experiments as a function of the polarity of the medium in the presence of both polar and nonpolar solvents showed that the hydrolysis rate is inversely proportional to the medium polarity. Ionic strength experiments showed that the hydrolysis rate is inversely proportional to the ion concentration.

Carbaryl toxicity, metabolism, and distribution in adults of three species of grass bugs _from the genus Labops were studied in relation to species, sex, and treatment with piperonyl butoxide. Lc50 values for 8 hour exposure periods ranged from 0.02-0.14, 0.03-0.3, and 0.2-0.7 μg carbaryl/vial for L. utahensis, L. hirtus, and L. hesperius respectively. The males were more susceptible to carbaryl than females. Males of L. utahensis were more susceptible than L. hirtus and L. hesperius respectively. The synergist difference values (Lc50 of carbaryl alone - Lc50 values of carbaryl after piperonyl butoxide treatment) were measured. The percent dependency of these _insects on MFOs for detoxifying carbaryl was estimated based on the theoretical synergist difference which was calculated by the equation Log LC50 = 1.014 log SD - 0.009. The percent dependency values were 38-59, 25-46, and 13-33% for L. hesperius, L. hirtus, and L. utahensis, respectively. Males of L. utahensis had the lowest percent dependency upon MFOs in detoxifying carbaryl (13%) indicating the possibility that carbaryl toxicity may be controlled by other potential defense mechanisms which are relatively ineffective themselves in view of the low tolerances of the insects to carbaryl. Treatment with piperonyl butoxide resulted in greater enhancement of carbaryl toxicity against L. hesperius (synergized Lc50 0.1-0.26 μg carbaryl/vial) while it showed a moderate effect on L. hirtus (synergized Lc50 0.02-0.16 μg carbaryl/vial). Piperonyl butoxide's effect was less pronounced in the case of L. utahensis (synergized Lc50 0.013- 0.09 μg carbaryl/vial. Unmetabolized carbaryl was the principle compound isolated from the bugs after 6 hours from treatment, being more prominent in males of L. hirtus (71.1% of the total metabolites) and less prominent in females hesperius (36.7% of the total metabolites). The mechanism of detoxication appeared to include ring hydroxylation for both species and sexes. 4 and 5-hydroxycarbaryl were the only metabolites associated with the degrading of carbaryl by the bugs, since the levels of metabolites obtained were too low for accurate quantitation. Pretreatment with piperonyl butoxide prevented the appearance of both carbaryl metabolites in the organosoluble fraction and increased the accumulation of unmetabolized carbaryl. This effect was probably due to inhibition of the insect's MFO system. Generally, this study showed a good correlation between the bioassays and the metabolic studies, thus reflecting the effectiveness of the bioassays along with synergist difference (SD) and percent dependency concepts in establishing some conclusions regarding the MFOs of Labops bugs. Further application of these techniques with agricultural insects should provide a practical means of characterizing field populations for insecticide tolerance, relative levels of MFOs and their role as a defense mechanism.