Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-05-04T13:38:40Z No. of bitstreams: 1 texto completo.pdf: 1561726 bytes, checksum: 03565d466784f0222c93947fb48f0d42 (MD5) / Made available in DSpace on 2017-05-04T13:38:40Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1561726 bytes, checksum: 03565d466784f0222c93947fb48f0d42 (MD5) Previous issue date: 2002-03-01 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Foram realizados três experimentos com o herbicida imazapyr, em casa de vegetação, com o objetivo de avaliar, por meio de bioensaios, a tolerância de diferentes genótipos de eucalipto ao herbicida e o potencial de exsudação radicular apresentado por Eucalyptus grandis. No estudo sobre tolerância de genótipos utilizaram-se mudas clonais de eucalipto de diferentes procedências, sob cultivo hidropônico, submetidas a diferentes doses de imazapyr. Os resultados evidenciaram comportamentos distintos entre os genótipos avaliados quanto à presença do herbicida em solução, indicando atenção à escolha de doses, sendo estas dependentes do clone utilizado. Quanto à exsudação radicular de imazapyr e, ou, seus metabólitos, foram usadas mudas clonais de E. grandis cultivadas em sistema hidropônico e em recipientes com solo, submetidas à aplicação foliar de imazapyr. Utilizou-se como bioindicadores da presença do herbicida no meio mudas de E. grandis, para o ensaio realizado sob sistema hidropônico, e sementes pré-germinadas de sorgo e pepino, para o ensaio em solo. Verificou-se que o E. grandis apresentou exsudação radicular de imazapyr e, ou, seus metabólitos tóxicos, em solução e no solo, em concentrações capazes de afetar o crescimento dos bioindicadores utilizados, além do fato de que, sob a menor dose utilizada, ocorreu inibição total da emissão de brotações após o corte do eucalipto. Os resultados obtidos sugerem a necessidade de investigações quanto ao destino final da molécula após o seu uso nos sítios de cultivo de eucalipto, bem como sua interferência no meio ambiente. / Three experiments were carried out to evaluate the tolerance of different eucalyptus genotypes to the herbicide imazapyr and the radicular exudation potential presented by Eucalyptus grandis, through bioassays, under greenhouse conditions. For the genotype tolerance study, hydroponically cultivated clonal eucalyptus seedlings of different origins were submitted to different doses of imazapyr. The results showed distinct responsesamong the genotypes evaluated in relation to the presence of the herbicide in the solution, indicating that attention should be given to the choice of doses, which will depend on the clone used. As for radicular exudation of imazapyr and/or its metabolites, E. grandis clonal seedlings were cultivated both hydroponically and in containers with soil, and submitted to imazapyr foliar application. E. grandis seedlings were used as bioindicators of the presence of the herbicide in the hydroponic cultivation assay and pre-germinated sorghum and cucumber seeds in the soil assay. E. grandis was found to present radicular exudation of imazapyr and/or of its toxic metabolites, in solution and in soil in concentrations that could affect the growth of the bioindicators used. Besides, under the lowest dose used, total inhibition of sprouting emission occurred after the eucalyptus was cut. The results obtained suggest the need for further investigation on the final fate of the molecule after its use in eucalyptus cultivation sites, as well as its interference in the environment. / Não foi localizado o cpf do autor.

A rapid primary herbicide screening experiment was conducted to determine if synergism or antagonism occurs with imazapyr(Arsenal&#174;) plus triclopyr ester (Garlon 4®) and imazapyr plus glyphosate(Accord®) mixtures applied to woody weed seedlings. Using a booth sprayer, 66 herbicide treatments were applied to greenhouse grown black cherry (Prunus serotina), winged elm (Ulmus alata), sweetgum (Liquidambar styraciflua), red maple (Acer rubrum), black locust (Robinia psuedoacacia), loblolly pine (Pinus taeda), water oak (Quercus nigra) and cabbage palmetto (Sabel palmetto). The seedlings were rapidly screened and percent mortality, height and dry weight measurements were obtained five months after treatment. The sweetgum, red maple and black locust experienced unacceptable mortality in the control treatments, and were excluded from further analysis. A determination of synergistic or antagonistic interactions was made using response surface analysis, the nonlinear blending method, the isobologram method, and the Colby method. Imazapyr plus triclopyr ester mixtures were found to be synergistic on black cherry (p < 0.05), with antagonism occurring at high rates of both herbicides. Imazapyr plus triclopyr ester was additive on the remaining species. The imazapyr plus glyphosate mixtures were found to be additive for all tested species. / Master of Science

No description available.

The stability of railway embankment is essential for safe transport. In order to ensure safe transport, water should be allowed to freely drain. Furthermore, as the engine driver has to be able to see signs, and people working on the embankment are supposed to easily see flaws on the rails to ensure safety for the passing trains, plants should not be allowed to grow on the embankment. In Sweden there are 12 000 kilometers of railway tracks and 25–30 % of them are treated for weed control every year. The Swedish Transport Administration is currently using the pesticide “Roundup Bio” to remove weeds on the embankment. To prevent the dispersal of chemicals to sensitive ecosystems, chemical transport has to be investigated carefully. In this master thesis a transport model for the transport of pesticides has been simulated using the software “GoldSim”. The model have been developed, optimized and controlled by a sensitivity analysis. In addition to this an analysis of worst case scenarios has been tested. The pesticides “Arsenal 250” with the active substance imazapyr and “Roundup Bio” with the active substance glyphosate have been used in the calibrating of the model. The transport model for imazapyr shows a good estimation of the mass of herbicides in the embankment compared to measurements. There is also a good estimation in the groundwater even if the concentration at the beginning of the simulation period is underestimated. The simulation with glyphosate, on the on the other hand, showed very small quantities of both glyphosate and its degradation product AMPA (aminometylphosphateacid) in both the embankment and in the groundwater. The sensitivity test showed that the parameter half-life and Kd-value (adsorption capacity) were the most sensitive parameters in the model. When it comes to the concentration in the groundwater the distance to the groundwater level was the most sensitive parameter, as well as the Kd-value in the embankment, the half-life and the precipitation. As expected, the worst-case analysis showed that a small distance to the groundwater level, a low Kd-value and a short half-life produced even larger concentrations of herbicides in the groundwater. In conclusion it should be mentioned that the stimulation model generally works well in regards to with imazapyr. For stimulation of glyphosate and its metabolite AMPA more work with the model is required for the Swedish Transport Administration to apply it in the future.

Phragmites australis (hereafter Phragmites) often forms dense monocultures, which displace native plant communities and alter ecosystem functions and services. Managers tasked with controlling this plant need science-backed guidance on how to control Phragmites and restore native plant communities. This study took a large-scale approach - to better match the scale of actual restoration efforts - to compare two herbicides (glyphosate vs. imazapyr) and application timings (summer vs. fall). Five treatments were applied to 1.2 ha plots for three consecutive years: 1) summer glyphosate; 2) summer imazapyr; 3) fall glyphosate; 4) fall imazapyr; and 5) untreated control. Dead Phragmites following herbicide treatments was mowed in the first two years. Efficacy of treatments and the response of native plant communities were monitored for three years. We report that fall herbicide applications were superior to summer applications. No difference was found between the two herbicides in their ability to reduce Phragmites cover. Plant communities switched from emergent to open water communities and were limited by Phragmites litter and water depth. Although, some plant communities showed a slow trajectory towards one of the reference sites, cover of important native emergent plants did not increase until year three and remained below 10%. These results suggest that fall is the best time to apply herbicides for effective large-scale control of Phragmites. Active restoration (e.g. seeding) may be needed to gain back important native plant communities. Methods to reduce Phragmites litter after herbicide applications should be considered.

Many fire-prone forests in western North America suffer from hazardous fuel conditions. Mechanical mastication is an increasingly common method of fuels treatment, but little is known regarding long-term effectiveness. A randomized block design at two sites (northern Sierras and southern Cascades) compared ladder fuels and overstory growth among treatments including mastication alone and mastication followed with prescribed fire or herbicide 10 or 11 years post-treatment. Subsequent herbicide application reduced ladder fuels in comparison to mastication alone or with prescribed fire. Prescribed fire further reduced ladder fuels at the southern Cascades site, however, in the northern Sierras postire ladder fuels were positively related to overstory absence. Mastication alone effectively released ponderosa pine at the southern Cascades site, whereas neither herbicide nor prescribed fire affected pine radial growth. This study demonstrates the feasibility of prescribed fire and herbicide for increasing treatment longevity of mastication, but also highlights potential limitations and important considerations.

Repeated partial cutting in the Appalachian hardwood region has often favored the development of tolerant species like American beech (Fagus grandifolia Ehrh.) and stands with a high proportion of cull trees. Crop tree release is a widely recommended practice to improve species composition and growth rates in these unevenaged structured stands. Chemical control offers some distinct advantages from the standpoint of safety and residual stand damage, over mechanical methods. Control of American beech was the primary focus of this study. Beech is a low value timber tree, normally considered difficult to control. It is a major competitor to more valuable trees, especially on better sites in the Appalachians. Research plots were established in hardwood stands at three sites in central West Virginia to evaluate the effectiveness of glyphosate (Accord), imazapyr (Arsenal AC and Chopper), and triclopyr (Garlon 3A and Garlon 4) using the hack-and-squirt application method and low volume basal spray treatments. In the injection treatments .051 fl oz (1.5 ml) of solution was used per inch of diameter (dbh). The basal spray treatments used 0.101 fl oz (3 ml) of solution per inch of diameter. The following concentrations were used: Accord (65.2%), Arsenal AC (7.5%), Garlon 3A (50%), Garlon 4 (26.25%), and Chopper (6.25% ). These concentrations were determined by using the highest costing injection and basal treatment at the lowest recommended labeled rate as standards, Garlon 3A and Chopper respectively. Eighteen 0.1 acre plots were systematically located at each study site where crop trees were present and to maximize the number of American beech on each plot. Crop trees, mostly black cherry (Prunus serotina Ehrh.) were chosen on a 0.025 acre subplot established at each plot center. All beech two inches and larger on the 0.1 acre plots and competing trees touching crop trees were treated in June 1998. The treatments were evaluated in September of 1998 and again in June of 1999. A numerical rating system ranging from 1-7, (0-100% crown affected), which utilized visual symptoms, was used to evaluate the efficacy of each treatment. Trees receiving a rating of 5 (75 % crown control) or greater were considered controlled. The relationship between the kinds of herbicide, application method, and numerical rating were analyzed by means of one-way analysis of variance with an incomplete random factorial design. The most effective treatments for the three month evaluations were the Accord and Garlon 3A injection treatments. Average beech crown control ranged from 95-99% for Accord to 96-99% for Garlon 3A across all study sites. The basal spray treatments were not effective. Average crown control ranged from 1-22%, across all study sites. Accord, Garlon 3A, and Arsenal AC were the most effective treatments for the 12 month evaluations, with average beech crown control ranging from 99-100% across all study sites. The imazapyr treatments (Arsenal Ac and Chopper) had adverse effects on the crop trees and are not recommended for hardwood crop tree release. The cost effectiveness based on treatment costs and the amount of basal area (BA) controlled were averaged for all study sites. The average treatment costs based on the 12 month evaluations expressed in dollars/ft2 BA controlled were as follows: Accord ($0.91), Garlon 3A ($1.04), Arsenal AC ($0.84), Garlon 4 ($15.09), and Chopper ($7.74). NE-TWIGS was used to predict future composition and value of the projected stands. The stem injection treatments decreased the amount of beech and increased the amount of black cherry sawtimber thereby dramatically increasing the future value of the stands. Real rates of return were calculated for the stem injection (8.81%) and low-volume basal spray (-0.81%). / Master of Science

Chemical site preparation is used to enhance the productivity of loblolly pine plantations; however, it is most often combined with other methods and/or chemical release, and has been studied little on its own. Our study, conducted in the Virginia piedmont, compares the effects of various site preparation applications of imazapyr and their timings (July 23rd, September 3rd, and October 1st 2005) against a year-two chemical release (September 12th 2007), and an untreated check, all following a site preparation burn (June 15, 2005). Testing for additive effects, site preparation treatments were conducted with and without, sulfometuron methyl (SMAX) which targets herbaceous vegetation. Half of all treatments, including the check and release, received a year-one weed control treatment (H) of imazapyr and SMAX. Pines were measured every few years, including the latest measurement in year 14 (2019). Competing hardwood vegetation basal area was measured in year 14. All site preparation treatments reduced competition levels compared to the check, and an inverse relationship exists between competition level and pine volume. Adding SMAX resulted in less effective competition control, but had little effect on pine volumes. Adding H decreased average competition levels, and increased pine volumes. H treatments had the most effect at improving early season (July) applications. September and October treatments generally had more effect than July and the year-two release at controlling competing vegetation, and also showed higher individual pine tree volumes than all other treatments. Chemical site preparation treatments, even performed alone, appear to be valid means of improving pine stands. / Master of Science / Competing vegetation has a negative effect on planted pine production. Areas are often prepared with herbicides or mechanical removal of vegetation before crop-trees are planted (site preparation), or receive herbicide treatments after planting (release), to reduce levels of competition. Our study focuses on pre-planting herbicide (imazapyr with and without sulfometuron methyl) use at different timings (July 23rd, September 3rd, and October 1st). A chemical that targets herbaceous vegetation (sulfometuron methyl) was included in half of the pre-planting treatments, and half of all treatments, including the otherwise untreated check and year-two release, received an added weed control treatment in year-one. This was done to test for potential additive effects of chemical vegetation control options on pine productivity. September and October treatments have a greater effect at controlling competition 14 years since treatment and increasing pine volumes than the July, year-two release, and check. The added herbaceous control increased competition levels on average, without having an effect on the planted pine volumes. The year-one weed control decreased competition levels, and increased pine productivity, particularly within the July treatments. Overall, preparing sites with herbicide is beneficial to the pine stand, even when performed alone. Adding the herbaceous vegetation control is likely not necessary, and the extra year-one weed control may provide a boost to herbicide treatments applied earlier in the season.

Prescribed fire and imazapyr are two silviculture tools used to control hardwood midstory competition in intensively managed, mid-rotation pine (Pinus spp.) stands but also may support conservation of biodiversity in the southeastern United States. Therefore, I investigated select measures of biodiversity response, small mammals, reptiles, amphibians, carabid beetles, songbirds, and vegetation communities, to fire and imazapyr treatments in intensively managed, mid-rotation pine stands of east-central Mississippi. I used a randomized complete block design of 6 stands (blocks) with 4, 10- ha treatment plots assigned randomly a treatment of burn only, herbicide only, burn + herbicide, or control. I applied dormant season prescribed fires every 3 years beginning in January 2000 and a one-time application of imazapyr in September 1999 using 877 ml/ha (12.0 liquid oz./ac; Arsenal®, BASF 2006). I sampled avifauna, herpetofauna, small mammal, and carabid beetle communities using appropriate sampling techniques for attaining species-specific relative abundance. I also measured vegetation structure and biomass. Vegetation and bird communities exhibited significant responses to treatments. Imazapyr had the greatest initial impact on communities followed by a long-term effect of repeated prescribed fires on a 3 year fire-return interval. Combining fire and imazapyr perpetuated high-quality browse for white-tailed deer (Odocoileus virginianus), plant species richness, high-priority bird species relative abundances, and diversity of landscape-level vegetation structure and biomass by creating a two-tier vegetation structure (pine canopy and herbaceous understory). Independent treatments also were more effective management approaches to sustain biodiversity than controls by maintaining or increasing overall species richness specifically soon after treatment application. Most responses of other wildlife communities were time-limited suggesting the possibility of greater effects of factors other than treatments such as long-term disturbance regimes (e.g., forest management practices, climate trends), proximity of treatment plots to wetlands, and landscape-level population dynamics including characteristics within and among stands. Combined and independent applications of these treatments will support biodiversity conservation, sustainable forestry objectives, and concomitant timber management goals. Long-term conservation of biodiversity within an intensive timber management matrix also may benefit from future investigations of multiple-herbicide tank mixtures, population dynamics of indicator species, and landscape-level biodiversity responses across multiple strata.