Browsing by Author "Fred P. Hain, Committee Member"

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    Anthropogenic Drivers of Gypsy Moth Dispersal.
    (2009-04-16) Bigsby, Kevin M; Erin O. Sills, Committee Chair; Fred P. Hain, Committee Member; Heather M. Cheshire, Committee Member; Patrick C. Tobin, Committee Member
    Gypsy moth (Lymantria dispar: Linnaeus) is a polyphagous non-native forest pest first introduced to Medford, Massachusetts in 1869. It has since spread as far south as North Carolina and as far west as Wisconsin. Gypsy moth is responsible for defoliating approximately 100,000 hectares of forest annually, resulting in mortality in a small percentage of trees, averting behavior by recreators, and creating a nuisance to the general public. Limiting the spread of gypsy moth is beneficial because it delays the onset of costs and losses associated with quarantine, tree defoliation and mortality, and nuisance. Gypsy moth is believed to disperse naturally up to 2.5 km/yr (e.g. early instar ballooning) but has been observed to disperse much greater distances. The scientific consensus is that this longer distance dispersal occurs through anthropogenic vectors (e.g. egg masses being transported on firewood). Despite the resources that United States Department of Agriculture and state agencies dedicate to eliminating and managing new infestations resulting from long distance dispersal, there has been limited empirical research on the relationship between the dispersal of gypsy moth and the movement of people and their goods. This thesis develops a conceptual framework of the anthropogenic factors that could affect dispersal, measures these factors with secondary data at the county level from a variety of sources, and estimates the presence or absence of gypsy moth using logistic regression models. The dependent variable is drawn from trap catch records archived by the United States Department of Agriculture Forest Service program, Slow-the-Spread, in areas distal to the 1 moth/trap line between 1999 and 2007. Through step-wise logistic regression estimating sub-models that include variables representing each broad anthropogenic factor, a final empirical model is specified. The variables of the model are estimated independently for each year from 1999 to 2007, resulting in a mean Pseudo R square of 0.568. Consistently significant ( ) anthropogenic variables are the number of households using wood for heating fuel and mean household income. These findings are discussed with regard to invasion theory and quarantine policy. One key implication is the continual importance of regulating and raising awareness about the risk of moving firewood from infested to uninfested zones.
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    First Report of the Repellency of 2-Tridecanone in Ticks
    (2010-04-14) Kimps, Nicholas Wade; Fred P. Hain, Committee Member; Charles S. Apperson, Committee Co-Chair; R. Michael Roe, Committee Co-Chair
    The chemicals 2-tridecanone and 2-undecanone are both found naturally in the trichomes of wild tomato plants and are important in plant resistance to herbivory. 2-Undecanone recently was shown to be an effective tick repellent and is the active ingredient in the commercially available arthropod repellent, BioUD®®. The goal of this study was to examine, for the first time the, tick repellency of 2-tridecanone. Two-choice bioassays were conducted between 8% 2-tridecanone versus the repellent carrier, absolute ethanol and compared to similar choice studies with 8% 2-undecanone versus absolute ethanol. Unfed, host-seeking adult (mixed sexes) Amblyomma americanum and Dermacentor variabilis were used to evaluate repellency and time to repellent failure at room temperature on two different substrates. In filter paper assays, 2-Tridecanone was >70% repellent to A. americanum and D. variabilis for 12 and 15 h, respectively. In contrast, 2-undecanone was >70% repellent to A. americanum and D. variabilis for only 2 h. In two choice assays on cheesecloth, 2-tridecanone was 85% repellent to A. americanum for 6 h. 2-tridecanone provided repellency significantly longer than 2-undecanone. The potential use of 2-tridecanone as a tick repellent is discussed.