Thesis (Ph. D.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references.

Thesis (Ph.D.(Plant Pathology))--University of Pretoria, 2005. / Abstract in English. Includes bibliographical references.

Master of Science / Department of Statistics / Leigh Murray / An experiment was performed in 2005-2006 to determine if the variety of an alfalfa (Medicago sativa) crop rotation can effectively reduce the pest complex consisting of the yellow and purple nutsedge (YNS & PNS) weeds and the southern root-knot nematode (SRKN). During the 2005-2006 growing season, six months were selected to take samples from the alfalfa field (three months in 2005 and three months in 2006). The field was divided into 1m x 2m quadrats. Each month eighty quadrats were randomly selected. The counts of PNS, YNS and a soil sample (analyzed for the count of juvenile SRKN) were taken from each quadrat. In this study, two different ways were examined use [i.e. using] spatial information provided from the experiment to alter the original model. First spatial information was treated as fixed effects. Second spatial information was treated as random effects by modifying the residual variance matrix using various “spatial” variance-covariance structures. The results were compared to the original Poisson model and the spatial models to each other but did not have an effective way of comparing random effects models with the fixed effects models. For this data, the use of spatial statistics did not improve the original model consistently. This may be partly because of the nature of the experiment. The alfalfa effectively reduced the YNS, PNS, and SRKN counts. The spatial information was generally more useful earlier in the experiment when the YNS, PNS, and SRKN populations were denser.

Thesis (M.S.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references.

Please read the abstract in the 00front part of this document. / Dissertation (MSc Agric (Weed Science))--University of Pretoria, 2001. / Plant Production and Soil Science / Unrestricted

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Repeat sequential applications (1 - 4) of imazaquin herbicide were applied to 100% pure stands of purple nutsedge during the summer of 198& Treatments were applied every two weeks. Maximum suppression for plots receiving only one application was reached 1 month after application (25% control). Two 14-day sequential applications achieved 60% control 2 weeks after the second treatment. Both 3 and 4 sequential applications resulted in 88% and 92% control after 2 and 4 weeks from the third and fourth applications, respectively. Resprouting eventually reoccurred on all plots. This data shows the enhanced effect of repeat applications of imazaquin for purple nutsedge suppression.

A field test was implemented at Paradise Valley Country Club to investigate the effect of two rates of imazaquin (Image) herbicide (0.38 and 0.50 lbs ai /a) in both the granular (G) and emulsifiable concentrate formulation on purple nutsedge and common bermudagrass in a mixed stand (85 ± 20% nutsedge).

An experiment was devised to evaluate application technique, and elucidate the plant response (herbicidal activity) of imazaquin herbicide on single plants of purple nutsedge. Herbicide treated plants showed increased filleting and stunting 31 days after treatment. Soil treatments tended to increase herbicidal response. Imazaquin activity was minimized when the herbicide was not irrigated into the soil. Soil applied-imazaquin postponed the emergence of shoots from viable nutlets, but did not prevent emergence altogether.