Submitted by MARIANA SILVEIRA BATISTA null (mariana.silveira.batista@hotmail.com) on 2016-10-12T22:01:12Z No. of bitstreams: 1 dissertação Mariana-corrigida20-07.docx: 5602251 bytes, checksum: d476cdd6d6522878deeae43655adee21 (MD5) / Rejected by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo as orientações abaixo: A versão final da dissertação/tese deve ser submetida no formato PDF (Portable Document Format) e o arquivo não deve estar protegido. Por favor, corrija o arquivo PDF e realize uma nova submissão com o arquivo desprotegido. Agradecemos a compreensão. on 2016-10-18T17:50:01Z (GMT) / Submitted by MARIANA SILVEIRA BATISTA null (mariana.silveira.batista@hotmail.com) on 2016-10-24T03:16:28Z No. of bitstreams: 1 dissertação Mariana-corrigida20-07.pdf: 1588233 bytes, checksum: d5c890fad0f53efad2f96d6713b49c42 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-10-24T18:26:21Z (GMT) No. of bitstreams: 1 batista_ms_me_ilha.pdf: 1588233 bytes, checksum: d5c890fad0f53efad2f96d6713b49c42 (MD5) / Made available in DSpace on 2016-10-24T18:26:21Z (GMT). No. of bitstreams: 1 batista_ms_me_ilha.pdf: 1588233 bytes, checksum: d5c890fad0f53efad2f96d6713b49c42 (MD5) Previous issue date: 2016-03-30 / A planta daninha está entre as espécies de maior importância nos campos de diversas culturas. Por se tratar de uma espécie que apresenta alto poder de produzir milhares de sementes que tem se adaptado ao uso de herbicidas, seu estudo se torna de grande importância para amenizar os danos causados às culturas. O trabalho foi desenvolvido com o objetivo de estudar as características morfofisiológicas da espécie Conyza canadensis (L.) Cronquist quanto à resistência ao herbicida do grupo químico das glicinas substituídas em plantas com histórico de resistência. O experimento foi instalado e conduzido durante o segundo semestre de 2014 em condição de campo na área da Universidade Federal do Mato Grosso do Sul – Campus Chapadão do Sul. O delineamento experimental foi blocos casualizados, com 4 repetições, os tratamentos em esquema fatorial 5x5, totalizando 25 tratamentos. O fator A correspondeu ao estádio de desenvolvimento: Tamanho I – plantas com 5 cm de altura; Tamanho II - 10 cm de altura; Tamanho III – 15 cm de altura; Tamanho IV – 20 cm de altura; Tamanho V – 25 cm de altura. O fator B foram as doses do glyphosate: Dose I (sem aplicação) - Testemunha; Dose II (1200 g i.a ha-1); Dose III (2400 g i.a ha-1); Dose IV (3600 g i.a ha-1) e Dose V (4800 g i.a ha-1). Foram realizadas análises de crescimento das plantas: altura de plantas e diâmetro do caule, aos 0, 14 e 28 dias após a aplicação dos tratamentos e uma avaliação de altura de plantas remanescentes ou rebrota realizada aos 100 dias após a aplicação. Para a análise de perdas de transpiração de folhas destacadas e hidratadas as plantas estavam em fase vegetativa e coletadas no terço-médio das plantas aos 0, 4 e 8 DAA. Os dados foram submetidos à análise de variância e as medias dos tratamentos comparadas pelo Teste de Scott Knott a 5% de probabilidade. Concluiu-se que tanto o tamanho das plantas como as doses do glyphosate influenciaram na altura de plantas, no diâmetro da haste e nas perdas de transpiração da espécie Conyza canadensis (L.) Cronquist. A porcentagem de redução da altura das plantas de tamanho menor foi maior conforme as doses de glyphosate aumentaram em todos os períodos das avaliações. Plantas de tamanho menor transpiram mais do que plantas de tamanho maior sem a aplicação de herbicida. Para as perdas de transpiração, as plantas de menor tamanho que receberam a aplicação do glyphosate em doses maiores, transpiraram menos. As plantas de tamanhos maiores transpiraram mais quando submetidas a doses medianas do glyphosate quando comparadas as doses maiores. / The weed is among the species of greatest importance in the fields of different cultures. Because it is a species that has a high power to produce thousands of seeds that have adapted to the use of herbicides, their study becomes very important to mitigate the damage to crops. The work was to study the morphological and physiological characteristics of species Conyza canadensis (L.) Cronquist for resistance to the herbicide chemical group of glycines substituted in plants with a history of resistance. The experiment was installed and conducted during the second half of 2014 under field conditions at the Universidade Federal do Mato Grosso do Sul-Campus Chapadão do Sul. The experimental design was blocks randomized with four repetitions, the treatments in a factorial 5x5, totaling 25 treatments. The factor A corresponded to the stage of development: Size I - plants with 5 cm; Size II - 10 cm; Size III - 15 cm; Size IV - 20 cm; Size V - 25 cm. The factor B were the glyphosate doses: Dose I (without application) - witness; Dose II (1200 g a.i. ha-1); Dose III (2400 g a.i. ha-1); Dose IV (3600 g a.i. ha-1) and Dose V (4800 g a.i ha-1). Plant growth analysis were performed: plant height and stem diameter at 0, 14 and 28 days after application of treatments and an assessment height of remaining plants or regrowth held at 100 days after application. For the analysis of transpiration losses highlighted and hydrated leaves the plants were in vegetative stage and collected the third-medium plants at 0, 4:08 DAA. The data were submitted to analysis of variance and the averages of the treatments compared by Scott Knott test at 5% probability. It was concluded that both the size of the plants as glyphosate doses influence on plant height, stem diameter and the losses in perspiration of species Conyza canadensis (L.) Cronquist. The percentage reduction of the height of the smaller plants was higher as the glyphosate rates increased in all periods of evaluations. smaller plants transpire more than plants of large size without the application of herbicide. For transpiration losses, smaller plants that received the application of glyphosate in larger doses, transpired less. The larger size plants transpired more when subjected to glyphosate median doses when compared to higher doses.

Orientador: Fernando Tadeu de Carvalho / Resumo: A planta daninha está entre as espécies de maior importância nos campos de diversas culturas. Por se tratar de uma espécie que apresenta alto poder de produzir milhares de sementes que tem se adaptado ao uso de herbicidas, seu estudo se torna de grande importância para amenizar os danos causados às culturas. O trabalho foi desenvolvido com o objetivo de estudar as características morfofisiológicas da espécie Conyza canadensis (L.) Cronquist quanto à resistência ao herbicida do grupo químico das glicinas substituídas em plantas com histórico de resistência. O experimento foi instalado e conduzido durante o segundo semestre de 2014 em condição de campo na área da Universidade Federal do Mato Grosso do Sul – Campus Chapadão do Sul. O delineamento experimental foi blocos casualizados, com 4 repetições, os tratamentos em esquema fatorial 5x5, totalizando 25 tratamentos. O fator A correspondeu ao estádio de desenvolvimento: Tamanho I – plantas com 5 cm de altura; Tamanho II - 10 cm de altura; Tamanho III – 15 cm de altura; Tamanho IV – 20 cm de altura; Tamanho V – 25 cm de altura. O fator B foram as doses do glyphosate: Dose I (sem aplicação) - Testemunha; Dose II (1200 g i.a ha-1); Dose III (2400 g i.a ha-1); Dose IV (3600 g i.a ha-1) e Dose V (4800 g i.a ha-1). Foram realizadas análises de crescimento das plantas: altura de plantas e diâmetro do caule, aos 0, 14 e 28 dias após a aplicação dos tratamentos e uma avaliação de altura de plantas remanescentes ou rebrota realizada aos ... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Horseweed (Erigeron canadensis) is a competitive winter or summer annual broadleaf weed. When uncontrolled, horseweed can reduce soybean (Glycine max) yields by 93%. Research was conducted to advance our knowledge on horseweed growth stage response to foliar-active and residual herbicides, fall applications, and the utility of differing herbicide technologies. Greenhouse results determined that herbicide efficacy was greatest when applied to early rosette horseweed providing an average control of 70% across herbicide treatments. Field trials determined that preventing new emergence with flumioxazin, added with dicamba or paraquat to kill existing plants in the fall, increased control to 99% the following spring. Field trials also determined that dicamba, applied PRE or POST, provided excellent horseweed control and was an effective soybean technology system for horseweed-infested fields. Saflufenacil controlled existing plants, but residual benefits were unclear. Further research must be done to investigate residual activity of PRE herbicides applied before horseweed emergence.

No description available.

Field and greenhouse studies were conducted in 2007 and 2008 to evaluate the foliar efficacy of saflufenacil on horseweed (Conyza canadensis (L.) Cronq.). In the field, saflufenacil applied alone at the lowest rate (25 g/ha) resulted in less control than all other herbicide treatments that included saflufenacil. The addition of glyphosate to 25 g/ha of saflufenacil increased the level of control over either herbicide applied alone. However, the addition of glyphosate to 50 g/ha of saflufenacil or greater was not beneficial because saflufenacil alone provided at least 95% control. Overall, horseweed height at the time of herbicide application had very little effect on the efficacy of saflufenacil applied alone or in combination with glyphosate. Application variables can enhance the foliar activity of saflufenacil. In the greenhouse, saflufenacil combined with glyphosate provided greater control than saflufenacil applied alone on both glyphosate-susceptible and -resistant horseweed populations. Regardless of horseweed population or glyphosate, saflufenacil had greater activity when crop oil concentrate rather than nonionic surfactant was used as the adjuvant. Decreasing light level within 24 hours of herbicide application resulted in greater saflufenacil activity. Applying saflufenacil in a pH 5 spray solution resulted in greater activity than pH 7 or pH 9. Although effects from saflufenacil applied under different temperatures were evident in early timings, there were no lasting effects on the efficacy of saflufenacil. Saflufenacil had significant activity on both glyphosate-susceptible and -resistant horseweed. Under certain conditions when complete control of horseweed is not achieved, such as low application rates, large target weeds, and varying environmental conditions, application variables including glyphosate tank-mixtures, crop oil concentrate, low spray solution pH, and low light level may increase the level of horseweed control from saflufenacil.

Horseweed has been documented in 70 countries and 40 different crops around the world and is listed as being a problem weed in no-till production systems. Horseweed has developed resistance to many herbicide modes of action including glycine. Field experiments were conducted from 2004 to 2006 in the Mississippi Delta to evaluate the field emergence of horseweed and most effective treatment programs for its control. Field emergence of horseweed was observed occurring primarily in the fall of the year, September through early November, when temperatures were between 15.6 to 23.4 C with later flushes occurring from late January through early April with temperatures ranging from 5.2 to 16 C. Tillage in September followed by herbicide in March gave 100% control of horseweed across all locations. Glyphosate + 2,4-D and glyphosate + dicamba were the best glyphosate-based treatments and provided 90% or better horseweed control 4 WAT both years. Glufosinate-based burndowns provided 81 to 97% horseweed control and soybean yields were generally similar with all glufosinate-based programs.

Cover crops have become an important part of cropping systems in the United States, especially in the Mid-Atlantic region. Rapeseed is a popular choice due to its deep growing taproot which creates soil macropores and increases water infiltration. If not properly terminated rapeseed can become problematic due to its pod-shattering tendency and its difficulty to terminate with herbicides once it enters reproductive growth. Results indicate termination of rapeseed is most effective when the cover crop is small. Combinations that successfully terminated rapeseed include glyphosate plus 2,4-D and paraquat plus 2,4-D. Halauxifen-methyl is a new Group 4 herbicide marketed for preplant burndown horseweed (Conyza canadensis L.) control. Previous research indicates that halauxifen effectively controls glyphosate-resistant horseweed. However, little is known about control of other common winter annual weeds by halauxifen. Results indicate halauxifen has a narrow spectrum of control providing adequate control (>80%) of horseweed, henbit (Lamium amplexicaule L.), and purple deadnettle (Lamium purpureum L.), while failing to control cutleaf evening-primrose (Oenothera laciniata Hill), curly dock (Rumex crispus L.), purple cudweed (Gamochaeta purpurea L. Cabrera), common chickweed (Stellaria media L.), and mousear chickweed (Cerastium L.). Little is known of cotton (Gossypium hirsutum L.) tolerance to halauxifen applied preplant burndown. Results indicate cotton is more tolerant to halauxifen than 2,4-D or dicamba when the interval between preplant application and cotton planting is less than 30 days. / Master of Science in Life Sciences / Cover crops are an important part of cropping systems in the United States, especially in the Mid-Atlantic region. Producers utilize cover crops to aid in weed suppression, reduce soil erosion, as well as to increase soil health. Cereals, legumes, and Brassicaceae species are popular cover crops planted either as monocultures or mixtures. Rapeseed can become problematic due to its difficulty to terminate once it enters reproductive stage, as well as its podshattering characteristic. Experiments were conducted to evaluate various herbicides and herbicide combinations for rapeseed termination two application timings. At three locations where rapeseed averaged 12 cm in height at early termination, and 52 cm in height at late termination, glyphosate + 2,4-D was most effective, controlling rapeseed (96%) 28 days after early termination (DAET). Paraquat + atrazine + atrazine (92%), glyphosate + saflufenacil (91%), glyphosate + dicamba (91%), and glyphosate (86%) all provided at least 80% control 28 DAET. Paraquat + 2,4-D (85%), glyphosate + 2,4-D (82%), and paraquat + atrazine + mesotrione (81%) were the only treatments to provide at least 80% control 28 days after late termination (DALT). At one location where rapeseed was much taller (41 cm early termination; 107 cm late termination), herbicides were much less effective, as no herbicide treatments provided greater than 80% control. Results indicated that rapeseed size at time of termination was more critical to successful termination than herbicide choice. Prior to the development of glyphosate-resistant horseweed, producers were able to control horseweed and other weeds with glyphosate applied preplant burndown. Producers now rely on auxin herbicides tank mixed with glyphosate and a residual herbicide to control horseweed and other winter weeds prior to cash crop planting. Experiments were conducted to evaluate halauxifen-methyl, a new Group 4 herbicide, for control of horseweed and other commonly encountered winter annual weeds. Halauxifen (89%) controlled small horseweed (<5 cm in height at time of application) similar to dicamba (91%), while providing better control of large horseweed (79%) (>15 cm in height at time of application) than either dicamba (77%) or 2,4-D evaluated (64%). Halauxifen provided adequate control (>80%) of henbit (Lamium amplexicaule L). and purple deadnettle (Lamium purpureum L.), while failing to effectively control of cutleaf evening-primrose (Oenothera laciniata Hill), curly dock (Rumex crispus L.), purple cudweed (Gamochaeta purpurea L. Cabrera), common chickweed (Stellaria media L. Vill.), and mousear chickweed (Cerastium L.). Results indicate that halauxifen has a narrow spectrum of control and should be tank mixed with 2,4-D or glyphosate in order to control weeds other than horseweed and henbit. Glyphosate plus dicamba or 2,4-D plus a residual herbicide is typically applied prior to cotton planting. Previous research has shown that as long as rainfall requirements and rotation intervals are met, no adverse effects on cotton is observed from 2,4-D or dicamba herbicides. Little is known of cotton tolerance to halauxifen applied preplant burndown. Experiments were conducted to determine if halauxifen applied sooner than the labeled 30-day rotation interval would injure cotton. Very little injury was observed from halauxifen (9%) applied at-planting, however dicamba (26%) and 2,4-D (21%) applied at the same timing did injure cotton. Auxin herbicides applied earlier in the season resulted in little injury (<2%). Early season injury was transient as cotton recovered later in the season and seedcotton yield was unaffected.

Thesis (M.S.)--Mississippi State University. Department of Plant and Soil Sciences. / Title from title screen. Includes bibliographical references.

Thesis (M.S.)--University of Tennessee, Knoxville, 2009. / Title from title page screen (viewed on Oct. 22, 2009). Thesis advisor: Lawrence E. Steckel. Vita. Includes bibliographical references.

Master of Science / Department of Agronomy / J. Anita Dille / Kraig Roozeboom / Increasing numbers of herbicide-resistant weed species require alternative methods of weed suppression to be examined. This study quantified the interaction between various cover crop or herbicide systems and horseweed [Conyza canadensis (L.)] growth. Fall cover crops of winter wheat [Triticum aestivum (L.)], winter rye [Secale cereal (L.)], barley [Hordeum vulgare (L.)] and annual ryegrass [Lolium multiflorum (L.)] were seeded in November 2012 and 2013. Spring cover crop of oat [Avena sativa (L.)] was seeded in April 2013 or rye was seeded in March 2014. All cover crops were no-till seeded into grain sorghum stubble [Sorghum bicolor (L.) Moench]. Four herbicide treatments were fall or spring applied, with and without residual. The spring non-residual treatment was also applied to plots of winter rye. Cover crop plots were split and terminated with a roller crimper or glyphosate application prior to soybean [Glycine max (L.) Merr.] planting to determine the effect of termination method on treatment performance. Soybean was planted in June 2013 and May 2014 and mechanically harvested in October of both years. Horseweed density, biomass accumulation, and soybean yield data were quantified. Horseweed height, whole plant seed production, and seed subsamples were recorded in the untreated fallow control, winter wheat, and winter rye plots in 2014. Horseweed suppression by winter rye approached 90%, levels similar to suppression by herbicide systems. In both years, herbicide plots had less than half the horseweed biomass than any of the cover crop systems. In 2013, soybean yields in herbicide plots were at least 1,500 kg ha[superscript]-1, nearly more than double yields in cover crop plots. Soybean yields in 2014 were more consistent across treatments; barley and spring rye plots achieved yields equal to or greater than 2,000 kg ha[superscript]-1. Winter rye and winter wheat reduced horseweed seed production by 60% compared to the untreated fallow control, with no effect on individual seed weight. Seed production varied across plants, with the untreated control producing the greatest number of seeds. Cover crops were successful at reducing horseweed biomass, suppressing horseweed pressure, preserving soybean biomass, and protecting soybean yields when compared to a fallow untreated control.