As the acreage of glyphosate-resistant (GR) cropping systems increases, so does the occurrence of herbicide-resistant weeds in the landscape. Biotypes of GR Conyza canadensis were first observed in Delaware, USA, in 2000. Since the first documentation of GR C. canadensis, there have been many instances of independent evolution of GR C. canadensis biotypes. The ecology of GR C. canadensis and any potential fitness consequences of GR trait are still unknown. If there is no fitness cost or a fitness increase associated with the GR trait, GR C. canadensis may increase in prevalence in the landscape even in the absence of glyphosate application. With the consideration that fitness is a difficult parameter to measure, other variables may be used as surrogate measures of fitness, such as reproduction, growth rate, phenology, survivorship, etc. This research seeks to determine if differences exist in surrogate measures of fitness - patterns of growth, reproductive allocation, and competitive ability - and if so, how differences may apply to future population changes, for glyphosate-resistant and -susceptible C. canadensis. The first two experiments presented test two populations of GR plants and two populations of GS plants, first in a greenhouse study of shading effects and intraspecific competition (Chapter 2), and second in a field survivorship study within two habitat types (Chapter 3). The third study tests for the prevalence of GR C. canadensis in field margins of GR cropping systems and seeks correlations in the occurrence of resistance and factors related to geography and field management (Chapter 4). The greenhouse study (Experiment 1, Chapter 2) of surrogate measures of fitness (growth, reproduction) in response to intraspecific competitive ability and shading showed that, while all populations had the same response to shading, there were differences between populations in growth and reproduction. While all measures were greater for individual plants with no competition, plants competing with individuals from one of the GR populations (R2) often had measures that were not different from the no competition treatment or were greater than the other competition treatments (R1, S1, and S2). The field survivorship study compared growth, survival, and reproduction of the previously studied four populations of C. canadensis is two habitats, a old-field in the second year of succession (ruderal) and a soybean field planted with a GR cultivar (agrestal) (Experiment 2, Chapter 3). One of the GR populations (R1) had the highest survivorship of the four populations in the ruderal habitat, while there was no difference in survivorship of the four populations in the agrestal habitat. While there was little difference in growth between ruderal populations, in the agrestal habitat, one GS population (S1) consistently had the smallest diameter, height, and leaf number. One of the agrestal GR populations (R2) was larger than the others, though not always different from R1. R1 was the first population to senesce regardless of habitat. Both agrestal GR populations produced more capitulae (seed heads) than the GS populations, and R1 also showed high reproductive success in the ruderal habitat. A test for the occurrence of GR C. canadensis in field margins of GR cropping systems (Experiment 3, Chapter 4) utilized a discriminating spray test on seed collected from the margins of 17 agricultural fields in 2008 from Illinois, Indiana, and Nebraska. The relationships between the occurrence of GR C. canadensis in 2008 field margins and 1) geography, 2) field management practices, 3) herbicide diversity, 4) weed community diversity, 5) field-interior changes in C. canadensis populations (λ), and 6) knowledge or suspicion of difficult-to-control C. canadensis populations, were tested. Geography was the clearest relationship in these data and was related to geography, with greater, more variable occurrence of GR C. canadensis in 2008 field margins in the southern and eastern sites than the northern and western sites. Management practices in field-interiors from year 2006 to 2008 had little relationship to occurrence of GR C. canadensis in 2008 field margins, except for the increased use of tillage and the increased use of non-glyphosate herbicide modes of action in 2007 field-interiors of fields with the highest occurrence of GR C. canadensis in the field margins in 2008. Additionally, the greatest occurrence of GR C. canadensis was associated with high diversity in the weed community in 2007 field-interiors. These results suggest that GR C. canadensis persisted in 2008 field margins even though there was a perceivable increase in management intensity the previous year. In conclusion, although there were no differences in fitness clearly associated with the GR trait in C. canadensis, GR populations may possess equal or greater vigor in growth, reproduction, and competition as GS populations. Based on these results, GR C. canadensis may persist in agricultural field-margins or other ruderal, unmanaged habitats and act as a seed source for future field-interior infestations. Depending on the characteristics of the GR biotype, GR C. canadensis may increase in frequency in the landscape.

Orientadores: Susanne Rath, Sonia Claudia do Nascimento de Queiroz / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-27T01:49:14Z (GMT). No. of bitstreams: 1 Porto_RafaelSilveira_M.pdf: 1983268 bytes, checksum: f89fcb853911e559df9889c577be5a8e (MD5) Previous issue date: 2015 / Resumo: O Brasil é um dos maiores produtores de frutas do mundo, no entanto, estima-se que doenças pós-colheita possam gerar perdas de até 50% em sua produção. A forma mais comum de tratamento para essas doenças envolve a aplicação de fungicidas sintéticos. Contudo, nos últimos anos, a demanda por tratamentos alternativos tem crescido, com destaque para o uso de biopesticidas, produtos desenvolvidos a partir de plantas, microrganismos e insetos. Este trabalho teve como objetivo investigar a presença dos compostos bioativos (4Z)-lachnophyllum lactona, (4Z,8Z)-matricaria lactona e (2Z,8Z)-matricaria ester nos espécimes brasileiros da planta Conyza canadensis, bem como avaliar a atividade antifúngica dessas substâncias isoladas contra diversos fungos associados a doenças pós-colheita de frutas. Por cromatografia flash preparativa foi possível isolar a (4Z)-lachnophyllum lactona e a (4Z,8Z)-matricaria lactona a partir de extratos da planta obtidos com diclorometano. Os compostos foram caracterizados por GC-MS/MS, NMR 1H e 13C, 1H-1H COSY e 1H-13C HSQC. Foram realizados ensaios de difusão em disco com 10 fungos filamentosos causadores de doenças pós-colheita em frutas. Os fungos Aspergillus niger, Cladosporium spp. e Penicillium digitatum se mostraram susceptíveis ao tratamento e, para eles, a concentração mínima inibitória dos compostos variou de 32 a 64 µg mL-1. Também foi desenvolvido um método de extração empregando água quente pressurizada, no qual foram otimizados os parâmetros de temperatura (100 °C), tempo de ciclo (1 min) e número de ciclos (quatro). Com essa técnica foi possível obter um rendimento de 1,46 mg g-1 e 0,24 mg g-1 para a (4Z)-lachnophyllum lactona e a (4Z,8Z)-matricaria lactona, respectivamente. O extrato aquoso da Conyza canadensis pode ser aplicado diretamente nos frutos com a vantagem de não conter resíduos de solventes orgânicos tóxicos / Abstract: razil is one of the largest fruit producers in the world. Nevertheless, it is estimated that postharvest diseases can lead to losses of up to 50% in its production. The most common treatment for these diseases involves the application of synthetic fungicides. Nonetheless, in recent years, the demand for alternative treatments has increased, especially for the use of biopesticides, products developed from plants, microorganisms and insects. This study aimed to investigate the presence of the bioactive compounds (4Z)-lachnophyllum lactone, (4Z,8Z)-matricaria lactone and (2Z,8Z)-matricaria ester in Brazilian specimens of the weed Conyza canadensis, as well as to evaluate the antifungal activity of these isolated substances against several fungi associated with postharvest diseases of fruits. With the use of preparative flash chromatography it was possible to isolate (4Z)-lachnophyllum lactone and (4Z,8Z)-matricaria lactone from plant extracts obtained with dichloromethane. The compounds were characterized by GC-MS/MS, NMR 1H e 13C, 1H-1H COSY and 1H-13C HSQC. Disk diffusion assays were performed in order to investigate the activity of the isolated compounds against 10 filamentous fungi regarded as common postharvest pathogens of fruits. Aspergillus niger, Cladosporium spp. and Penicillium digitatum proved susceptible to the treatment and, for them, the minimum inhibitory concentration of the compounds varied from 32 to 64 µg mL-1. An extraction method using pressurized hot water was also developed, in which the parameters of temperature (100 ° C), cycle time (1 min) and number of cycles (four) were optimized. By using this technique, it was possible to obtain a yield of 1.46 mg g-1 and 0.24 mg g-1 for the (4Z)-lachnophyllum lactone and (4Z,8Z)-matricaria lactone, respectively. The aqueous extract of Conyza canadensis can be applied directly on fruits with the advantage of not containing residues of toxic organic solvents / Mestrado / Quimica Analitica / Mestre em Química

Conyza bonariensis, flaxleaf fleabane, is a major weed threat on cultivated and non-cultivated lands, gardens, roadsides and waste places. The weed in South Africa is believed to have originated from South America, and the first herbarium sample is from a plant collected in May 1895 at Franschhoek. Adding to its problem status is the recent discovery that certain C. bonariensis biotypes in South Africa and other parts of the world are resistant to the herbicide glyphosate, and in certain cases to both glyphosate and paraquat. Despite its invasiveness and ability to compete severely with crops, the mechanisms of interference (= allelopathy + competition) employed by C. bonariensis are poorly understood and have not yet been thoroughly investigated. There is a need to expand on the knowledge of interference mechanisms of C. bonariensis in order to better understand its success as a weed, and to improve on knowledge for the successful management of this weed. In the present study, allelopathic potential of C. bonariensis was assessed, first by means of germination bioassays, followed by investigation employing hydroponics, leachate, and replacement series experiments. In a laboratory bioassay, the plant’s leaves and roots were extracted using two solvents, water and hexane, to which seeds of the test (acceptor) species lettuce (Lactuca sativa L.) and tomato (Lycopersicon esculentum) were exposed in order to determine where the strongest allelopathic potential resides. Moreover, differential potency of crude extracts prepared with the two solvents (polar and non-polar) would at least provide some evidence on the nature of putative allelochemicals involved. Germination bioassays revealed that leaves harboured the strongest allelopathic potential (potency). Water extracts (infusions) caused greater growth inhibition of the test species than hexane extracts. Osmolalities of the water infusions were tested and found not to be inhibitory to germination and early seedling development of lettuce. Following on the germination bioassays, a hydroponic experiment was set up in a greenhouse in order to investigate whether C. bonariensis possesses and releases chemicals with allelopathic potential through its roots. Lettuce top and root growth was significantly reduced by all three populations of C. bonariensis (one from Pretoria; two from the Western Cape). No significant differences were observed in the degree of growth inhibition caused by the three weed populations on the growth of lettuce, except in the case of root dry mass results where the Hatfield population caused more damage (85% growth reduction). The leachate experiment was then performed to determine if leachate from C. bonariensis affected the growth of test species exposed to different leachate concentrations. Although there was no growth inhibition observed for both lettuce and tomato in this experiment, growth stimulation of tomato roots was observed at the highest leachate concentration (100%). Finally, in an attempt to simulate the allelopathic potential of C. bonariensis in a natural field situation, a replacement series experiment was conducted to determine the relative interference of Conyza bonariensis in relation to lettuce and tomato. Dry mass results showed that there was no growth inhibition of both crop species. RYT was > 1 at all weed: crop combinations, which implies that both crop species and C. bonariensis were less affected by interspecific interactions than in their respective monocultures. It is suggested that the results of this study can attributed to methodology and growth media. The results of this study represent the first step in showing that allelopathic potential C. bonariensis may contribute to the success of this weed as an invasive weed species and that this weed should not be allowed to attain significant biomass on crop field. Further research should include field trials that will yield a better understanding of the practical relevance of the allelopathic potential of C. bonariensis. Finally, crop producers and weed management practitioners should recognize that this important weed has the ability to interfere with the growth and development of a crop through two mechanisms, competition plus allelopathy. / Dissertation (MInst Agrar)--University of Pretoria, 2013. / gm2014 / Plant Production and Soil Science / unrestricted

Conyza bonariensis (L.) is a native plant of South America, easily found in the south area. It s popular name is buva or margaridinha-do-campo. This plant is very used in folk medicine for rheumatism, gout, cystitis, nephrite, dysmenorrhea, tooth pain, headache. The main secondary metabolits present in the species Conyza bonariensis (L.) were flavonoids, saponins, organics acids, cardyotonic and phenols. In the volatile oil of the var. bonariensis two major constituents were identified, the ester cis-lachnophyllum methyl (78,69%) and ester matricaria methyl (17,67%) present in the roots, and the components cis-lachnophyllum methyl ester (44,31%) and the caryophyllene oxide (22,0%) present in the leaves. In the var. microcephala, the major constituents found in the root were the ester cis-lachnophyllum methyl (88,87%), and in the leaves the ester trans-lachnophyllum methyl (43,05%). The volatile oils of the var. bonariensis displayed antimicrobial activity against microorganisms Klebsiella pneumoniae, Escherichia coli, Candida albicans Saccharomyces cerevisiae. The plant didn't demonstrate acute oral toxicity, in the concentrations 250,500,1000 and 2000 mg/kg in mice. The ethyl acetate and buthanol fractions exhibided a significative antioxidant activity by DPPH and β-carotene method in the concentration of 62,5 μg/ml. The crude extract and the buthanol fraction expressed larger cytotoxic activity with CL50 27,35μg/ml, as the volatile oil of the roots of the var. bonariensis CL50 0,48μg/ml against Artemia salina. Thus, the present work aimed at contributing to the studies of the native herbs of the state of Rio Grande do Sul. / Conyza bonariensis (L.) é uma planta nativa da América do Sul, facilmente encontrada na região sul. É conhecida popularmente como buva ou margaridinha-do-campo. É utilizada na medicina popular para o reumatismo, gota, cistite, nefrites, dismenorréia, dor de dente, dor de cabeça. Os principais metabólitos secundários presentes na espécie Conyza bonariensis (L.) foram flavonóides, saponinas, ácidos orgânicos, cardiotônicos e fenóis. No óleo volátil da var. bonariensis identificou-se 2 componentes majoritários, o cis-lachnophyllum metil éster (78,69%) e matricaria metil éster (17,67%) presente nas raízes, e os compostos cis-lachnophyllum metil éster (44,31%) e o óxido de cariofileno (22,0%) presente nas folhas. Na variedade microcephala, o composto majoritário encontrado na raiz foi o cis-lachnophyllum metil éster (88,87%), e nas folhas o trans-lachnophyllum metil éster (43,05%). Os óleos voláteis da var. bonariensis apresentaram atividade antimicrobiana frente aos microrganismos Klebsiella pneumoniae, Escherichia coli, Candida albicans Saccharomyces cerevisiae. A planta não demonstrou toxicidade aguda, por via oral, nas concentrações 250, 500,1000 e 2000 mg/kg em camundongos. As frações acetato de etila e butanólica apresentaram boa atividade antioxidante pelo método DPPH e β-caroteno na concentração de 62,5 μg/ml. O extrato bruto e a fração butanólica expressaram maior atividade citotóxica com CL50 27,35μg/ml, bem como o óleo volátil das raízes da var. bonariensis CL50 0,48μg/ml frente à Artemia salina. Pretendeu-se com o presente trabalho contribuir para os estudos da flora nativa do Rio Grande do Sul

Made available in DSpace on 2016-12-08T16:44:47Z (GMT). No. of bitstreams: 1 PGPV14MA144.pdf: 861442 bytes, checksum: c0bd112f70401acc3674e49bcc979cf3 (MD5) Previous issue date: 2014-07-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of the present work is to analyze the response of plants of ryegrass (Lolium multiflorum) and wavy-leaved fleabane (Conyza bonariensis) to increasing doses of glyphosate to detect herbicide susceptible and resistant biotypes and to evaluate the physiological quality of seeds of these biotypes to verify the relationship between the resistance and the physiological seed quality of these weeds. Ryegrass and wavy-leaved fleabane plants were exposed to increasing doses of glyphosate, ranging from 0 up to 1440 g ae ha-1, and the fresh weight were weighted 21 days after application, for dose-response tests. Seeds were subjected to tests of physiological quality (germination, cold test and accelerated aging). The experimental design was completely randomized, using ten replicates for ryegrass and six replicates for wavy-leaved fleabane in the dose-response tests, and four replicates for tests of physiological seed quality. All studied biotypes of ryegrass and wavy-leaved fleabane showed differential response due to increasing doses of glyphosate. Ryegrass resistant biotypes showed resistance factors (RF) of 3.0 (Passo Fundo) and 8.3 (Vacaria), while the susceptible ones showed FR of 1.5 (Ponte Serrada) and 1.0 (Lages). Wavy-leaved horseweed resistant biotypes showed FR 2.0 (Papanduva) and 15.5 (Campos Novos), and the susceptible biotype FR 1.0 (Lages). In the tests of physiological seed quality, ryegrass biotype of Lages showed the best performance for germination (64%) and accelerated aging (86%) tests compared to the other biotypes. For the cold test, the biotype of Vacaria showed the best result with 86% of germination, while the biotype of Passo Fundo showed the worst results in all tests. Biotypes of wavy-leaved fleabane did not differ in germination. For Lages and Papanduva wavy-leaved fleabane, itwas found the biotypes responded positively to cold stress (66 and 61%, respectively). The biotype of Campos Novos, with high resistance to the herbicide, did not withstand the stress exposure, presenting similar to germination (34%) compared to the cold test (28%) result. The seeds of the wavy-leaved fleabane biotypes responded negatively to accelerated aging, in that the biotype of Lages showed the best result (12%), while biotypes of Papanduva and Campos Novos showed 4.0 and 2.0%, respectively. Biotypes of ryegrass with differential response to glyphosate present distinct percentage of germination and vigor of seeds, although it is not directly dependent on herbicide resistance. Susceptible biotypes of wavy-leaved fleabane and the biotype with low degree of resistance to glyphosate are more vigorous than the resistant biotype. The physiological seed quality of ryegrass and wavy-leaved fleabane is not directly related to the resistance to glyphosate, and the influence of environment is probably more significant than the resistance / Objetivou-se com o presente trabalho analisar a resposta de plantas de azevém (Lolium multiflorum) e buva (Conyza bonariensis) a doses crescentes do glyphosate para detecção de biótipos suscetíveis e resistentes ao herbicida e avaliar a qualidade fisiológica de sementes desses biótipos para verificar a relação entre a resistência e a qualidade fisiológica de sementes dessas plantas daninhas. Plantas de azevém e buva foram expostas a doses crescentes de glyphosate, variando de 0 a 1.440 g e.a. ha-1, com avaliação da massa fresca após 21 dias da aplicação. As sementes foram submetidas a testes de qualidade fisiológica (germinação, teste de frio e envelhecimento acelerado). O delineamento experimental utilizado foi o inteiramente casualizado, com dez repetições para o azevém e seis repetições para a buva no teste de dose-resposta e com quatro repetições para os testes de qualidade fisiológica de sementes. Todos os biótipos estudados de azevém e buva apresentaram resposta diferencial ao aumento de dose do herbicida glyphosate. Os biótipos de azevém resistentes apresentaram fatores de resistência (FR) igual a 3,0 (Passo Fundo) e 8,3 (Vacaria) enquanto os susceptíveis 1,5 (Ponte Serrada) e 1,0 (Lages). Os biótipos de buva resistentes apresentaram FR de 2,0 (Papanduva) e 15,5 (Campos Novos) e o biótipo susceptível FR de 1,0 (Lages). Nos testes de qualidade fisiológica o biótipo de azevém de Lages apresentou melhor desempenho para os testes de germinação (64%) e envelhecimento acelerado (86%) em relação aos demais biótipos. Para o teste de frio, o biótipo de Vacaria apresentou o melhor resultado com 86%. Enquanto que o biótipo de Passo Fundo apresentou os piores resultados em todos os testes realizados. Os biótipos de buva não se diferenciaram no teste de germinação. Para os biótipos Lages e Papanduva foi verificado que o vigor desses biótipos responderam positivamente ao estresse pelo frio (66 e 61% respectivamente). O biótipo de Campos Novos, com elevada resistência ao herbicida, não suportou a exposição ao estresse, apresentando resultado semelhante ao teste de germinação (34%) em relação ao teste de frio (28%). As sementes dos biótipos de buva responderam negativamente ao teste de envelhecimento acelerado, em que o biótipo de Lages apresentou o melhor resultado com 12%, enquanto os biótipos de Papanduva e Campos Novos apresentaram 4,0 e 2,0% respectivamente. Os biótipos de azevém com resposta diferencial ao glyphosate apresentam porcentagem de germinação e vigor de sementes distintos, porém não diretamente dependentes da resistência ao herbicida. Os biótipos de buva suscetível e com baixo grau de resistência ao herbicida glyphosate são mais vigorosos que o biótipo resistente. A qualidade fisiológica de sementes de azevém e buva não está diretamente relacionada com a resistência ao herbicida glyphosate, sendo a influência do ambiente, provavelmente, mais significativa do que a resistência

Casos reportados de buva com resistência ao glyphosate têm aumentado, ano após ano, a importância dessa planta daninha no cenário agrícola brasileiro. Com o intuito de entender alguns aspectos de sua biologia que resultem em manejo mais adequado, os objetivos deste trabalho foram: (i) identificar os períodos do ano em que ocorrem os maiores fluxos de emergência da buva e analisar seu crescimento e desenvolvimento em dois ambientes agrícolas distintos; (ii) avaliar os efeitos da cobertura vegetal e umidade em sua germinação e emergência; (iii) construir curvas de dose-resposta de um biótipo de Conyza bonariensis resistente ao glyphosate para herbicidas alternativos e (iv) avaliar as opções de manejo químico desse biótipo após o corte e rebrota. Para esses objetivos, experimentos foram conduzidos em campo e casa-de-vegetação nos municípios de Santa Cruz das Palmeiras, SP (SCP) e Não-Me-Toque, RS (NMT), entre maio de 2010 a maio de 2012. Em condições de campo, observou-se em SCP que a emergência da buva ocorre de forma escalonada, sendo mais concentrada no final do verão e início da primavera e a precipitação e a presença de pouca cobertura vegetal no solo parecem exercer mais influência que a temperatura. Em NMT, o fluxo de emergência é mais concentrado no inverno, em que a precipitação não é fator limitante, sendo a germinação e emergência favorecidas por temperaturas mais baixas. Nos dois locais, plantas que germinam na época mais fria do ano (julho) apresentam desenvolvimento inicial mais lento, com acúmulo de biomassa mais intenso e concentrado em torno dos 90-104 dias após a semeadura (DAS); plantas que germinam na primavera (setembro) também apresentam desenvolvimento inicial lento, porém seu crescimento é mais distribuído ao longo do tempo, com os picos de acúmulo aos 80-90 DAS. Em condições de casa-de-vegetação, a disponibilidade hídrica do solo foi mais importante para a emergência de plântulas de buva que a quantidade de cobertura vegetal (palha). Em solo úmido, menores quantidades de palha favorecem a emergência da buva em relação ao solo descoberto. Quantidades maiores de palha promovem supressão de sua emergência. A resistência ao glyphosate foi confirmada para o biótipo de C. bonariensis, coletado em SCP (biótipo B2) e a eficiência dos herbicidas alternativos foi diferente em função dos estádios de desenvolvimento desse biótipo no momento da aplicação. Os herbicidas metsulfuron, diclosulam, 2,4-D, dicamba, atrazine, glufosinate e paraquat foram os mais consistentes no controle do biótipo resistente, sendo que, no estádio mais avançado, a associação com glyphosate agregou no controle para metsulfuron, diclosulam e 2,4-D. Após o corte, controle mais eficiente da rebrota (biótipo B2) foi obtido quando a aplicação ocorreu no mesmo dia do corte que 7 dias depois e os tratamentos mais eficientes nas duas situações foram glyphosate + diclosulam, glyphosate + 2,4-D e 2,4-D. A associação de glyphosate aos tratamentos incrementou o controle da rebrota independentemente da época de aplicação. / Reported cases of glyphosate resistant hairy fleabane have increased its im-portance in Brazilian agricultural. To understand the key principles to effective man-agement, the objectives of this research were to: (i) analyze hairy fleabane growth and development patterns in two different agricultural environments during peak emergence, (ii) evaluate the effects of stover and soil moisture on seedling emer-gence, (iii) obtain dose-response curves for alternative herbicides in a Conyza bonariensis glyphosate-resistant biotype and (iv) evaluate chemical control options for this biotype after cutting and regrowth. For these objectives, experiments in the field and greenhouse were conducted in Santa Cruz das Palmeiras, Sao Paulo State (SCP) and Nao-Me-Toque, Rio Grande do Sul State (NMT), during May, 2010 to May, 2012. At SCP, the germination and emergence of hairy fleabane occurred cycli-cally, peaking more in late summer and early spring and influenced by increased rainfall. In addition, the presence of little crop residue or stover in the ground seemed to exert more influence than temperature. At NMT, emergence was more concen-trated during the winter, when precipitation is not a limiting factor. Germination and emergence were favored by lower temperatures. For both sites, plants that germinat-ed in the coldest season of the year (July) showed slower initial development, with a more intensive biomass accumulation and peaked around 90-104 days after planting. Plants that germinated in the spring (September) also showed slower initial develop-ment, but their growth was more evenly distributed over time, and peaked about 80-90 days after planting. In greenhouse conditions, soil water content was more im-portant for influencing seedling emergence of hairy fleabane than the amount of stover and the highest emergence was observed in moist soil. In the presence of moisture, lower amounts of stover increased seedling emergence of hairy fleabane compared to bare soil. The presence of large quantities of stover on the soil surface resulted in emergence suppression. Glyphosate resistance in Conyza bonariensis, biotype B2, was confirmed by dose-response curves with susceptible biotype. The efficacy of alternative herbicides was different depending on the stage of the resistant biotype at application timing. The herbicides metsulfuron, diclosulam, 2,4-D, dicamba, atrazine, glufosinate and paraquat were the most effective in controlling the resistant biotype. In later stages the association with glyphosate resulted in a better control with metsulfuron, diclosulam and 2,4-D. More efficient control of hairy flea-bane regrowth (biotype B2) was observed when herbicides were applied on the same day that the plants were cut than when applied 7 days after cutting. The most effec-tive herbicide treatments in both situations were glyphosate + diclosulam, glyphosate + 2,4-D, and 2,4-D alone. The association of glyphosate in the herbicide treatments increased control of hairy fleabane regrowth regardless of application timing.

Casos reportados de buva com resistência ao glyphosate têm aumentado, ano após ano, a importância dessa planta daninha no cenário agrícola brasileiro. Com o intuito de entender alguns aspectos de sua biologia que resultem em manejo mais adequado, os objetivos deste trabalho foram: (i) identificar os períodos do ano em que ocorrem os maiores fluxos de emergência da buva e analisar seu crescimento e desenvolvimento em dois ambientes agrícolas distintos; (ii) avaliar os efeitos da cobertura vegetal e umidade em sua germinação e emergência; (iii) construir curvas de dose-resposta de um biótipo de Conyza bonariensis resistente ao glyphosate para herbicidas alternativos e (iv) avaliar as opções de manejo químico desse biótipo após o corte e rebrota. Para esses objetivos, experimentos foram conduzidos em campo e casa-de-vegetação nos municípios de Santa Cruz das Palmeiras, SP (SCP) e Não-Me-Toque, RS (NMT), entre maio de 2010 a maio de 2012. Em condições de campo, observou-se em SCP que a emergência da buva ocorre de forma escalonada, sendo mais concentrada no final do verão e início da primavera e a precipitação e a presença de pouca cobertura vegetal no solo parecem exercer mais influência que a temperatura. Em NMT, o fluxo de emergência é mais concentrado no inverno, em que a precipitação não é fator limitante, sendo a germinação e emergência favorecidas por temperaturas mais baixas. Nos dois locais, plantas que germinam na época mais fria do ano (julho) apresentam desenvolvimento inicial mais lento, com acúmulo de biomassa mais intenso e concentrado em torno dos 90-104 dias após a semeadura (DAS); plantas que germinam na primavera (setembro) também apresentam desenvolvimento inicial lento, porém seu crescimento é mais distribuído ao longo do tempo, com os picos de acúmulo aos 80-90 DAS. Em condições de casa-de-vegetação, a disponibilidade hídrica do solo foi mais importante para a emergência de plântulas de buva que a quantidade de cobertura vegetal (palha). Em solo úmido, menores quantidades de palha favorecem a emergência da buva em relação ao solo descoberto. Quantidades maiores de palha promovem supressão de sua emergência. A resistência ao glyphosate foi confirmada para o biótipo de C. bonariensis, coletado em SCP (biótipo B2) e a eficiência dos herbicidas alternativos foi diferente em função dos estádios de desenvolvimento desse biótipo no momento da aplicação. Os herbicidas metsulfuron, diclosulam, 2,4-D, dicamba, atrazine, glufosinate e paraquat foram os mais consistentes no controle do biótipo resistente, sendo que, no estádio mais avançado, a associação com glyphosate agregou no controle para metsulfuron, diclosulam e 2,4-D. Após o corte, controle mais eficiente da rebrota (biótipo B2) foi obtido quando a aplicação ocorreu no mesmo dia do corte que 7 dias depois e os tratamentos mais eficientes nas duas situações foram glyphosate + diclosulam, glyphosate + 2,4-D e 2,4-D. A associação de glyphosate aos tratamentos incrementou o controle da rebrota independentemente da época de aplicação. / Reported cases of glyphosate resistant hairy fleabane have increased its im-portance in Brazilian agricultural. To understand the key principles to effective man-agement, the objectives of this research were to: (i) analyze hairy fleabane growth and development patterns in two different agricultural environments during peak emergence, (ii) evaluate the effects of stover and soil moisture on seedling emer-gence, (iii) obtain dose-response curves for alternative herbicides in a Conyza bonariensis glyphosate-resistant biotype and (iv) evaluate chemical control options for this biotype after cutting and regrowth. For these objectives, experiments in the field and greenhouse were conducted in Santa Cruz das Palmeiras, Sao Paulo State (SCP) and Nao-Me-Toque, Rio Grande do Sul State (NMT), during May, 2010 to May, 2012. At SCP, the germination and emergence of hairy fleabane occurred cycli-cally, peaking more in late summer and early spring and influenced by increased rainfall. In addition, the presence of little crop residue or stover in the ground seemed to exert more influence than temperature. At NMT, emergence was more concen-trated during the winter, when precipitation is not a limiting factor. Germination and emergence were favored by lower temperatures. For both sites, plants that germinat-ed in the coldest season of the year (July) showed slower initial development, with a more intensive biomass accumulation and peaked around 90-104 days after planting. Plants that germinated in the spring (September) also showed slower initial develop-ment, but their growth was more evenly distributed over time, and peaked about 80-90 days after planting. In greenhouse conditions, soil water content was more im-portant for influencing seedling emergence of hairy fleabane than the amount of stover and the highest emergence was observed in moist soil. In the presence of moisture, lower amounts of stover increased seedling emergence of hairy fleabane compared to bare soil. The presence of large quantities of stover on the soil surface resulted in emergence suppression. Glyphosate resistance in Conyza bonariensis, biotype B2, was confirmed by dose-response curves with susceptible biotype. The efficacy of alternative herbicides was different depending on the stage of the resistant biotype at application timing. The herbicides metsulfuron, diclosulam, 2,4-D, dicamba, atrazine, glufosinate and paraquat were the most effective in controlling the resistant biotype. In later stages the association with glyphosate resulted in a better control with metsulfuron, diclosulam and 2,4-D. More efficient control of hairy flea-bane regrowth (biotype B2) was observed when herbicides were applied on the same day that the plants were cut than when applied 7 days after cutting. The most effec-tive herbicide treatments in both situations were glyphosate + diclosulam, glyphosate + 2,4-D, and 2,4-D alone. The association of glyphosate in the herbicide treatments increased control of hairy fleabane regrowth regardless of application timing.

Made available in DSpace on 2016-12-08T16:44:48Z (GMT). No. of bitstreams: 1 PGPV14MA155.pdf: 1657059 bytes, checksum: db15b0066199e2467a255a01e90fc781 (MD5) Previous issue date: 2014-12-08 / This work aimed to study alternatives to chemical management of ryegrass and horseweed, taking into account environmental and biological factors at the time of application of herbicides, as well as the occurrence of resistant biotypes of these species. For that, two experiments were carried out. The first one aimed to evaluate the influence of air temperature and the phenological stage on the chemical control of ryegrass biotypes resistant and susceptible to glyphosate, being conducted in a greenhouse in a completely randomized design with four replicates and arranged in a factorial scheme 10x2x2x2. The herbicides clethodim, clodinafop-propargyl, fenoxaprop-p-etyl+clethodim, glyphosate, iodosulfuron-methyl, paraquat, paraquat+diuron, sethoxydim, and tepraloxydim were applied in glyphosate-resistant and -susceptible biotypes of ryegrass in air temperatures of 20-22 ºC and 30-34 ºC in the moment of the application and growth stages of 3-4 leaves and flowering. The weed control was assessed at 7, 14, 21, and 28 days after application, assigning the percentage from 0 to 100, corresponding to the absence of injury and death of plants, respectively. Plant height and dry weight of shoots were determined after the last evaluation of control. Data were subjected to analysis of variance and means were compared by Tukey test (p≤0.05). Paraquat and paraquat+diuron controlled ryegrass, regardless of biotype, stadium, and temperature of application. The other herbicides controlled ryegrass in the 3-4 leaf stage when applied to 20-22 °C , regardless of the biotype. Herbicides applied to 30-34 °C were not effective in controlling the resistant biotype in early stage. At flowering , tepraloxydim and fenoxaprop-p-ethyl+ clethodim provided greater control of the resistant biotype when applied at temperatures of 30-34 °C. The second experiment aimed to identify herbicides to alternative control of horseweed resistant to glyphosate, as well as the influence of the stage of plant development on the weed control. The experiment was conducted in apple orchard in an area with reports of horseweed survival after applying glyphosate. The design was a randomized block with four replicates and arranged in a factorial scheme 5x2, with the herbicides ammonium-glufosinate, bentazon, diquat, glyphosate, and glyphosate+saflufenacil that were applied into horseweeds in the pre-flowering stage and plant regrowth, 15 days after cutting plants. The weed control was evaluated at 7, 14, 21, and 28 days after application, assigning a percentage from 0 to 100, corresponding to the absence of injury and death of plants, respectively. Data were subjected to analysis of variance and means were compared by Tukey test (p≤0.05). The herbicides diquat, basagran, and glyphosate+saflufenacil were not effective in controlling horseweed in pre-flowering; ammonium-glufosinate proved to be a viable alternative to horseweed control in advanced stages. With the exception of glyphosate, all herbicide controlled the regrowing horseweed biotypes in apple orchard / Este trabalho visou estudar alternativas para o manejo químico de azevém e buva, levando em consideração fatores ambientais e biológicos no momento da aplicação dos herbicidas, bem como a ocorrência de biótipos resistentes dessas espécies. Para isso, foram realizados dois experimentos. O primeiro, teve o objetivo de avaliar a influência da temperatura do ar e do estádio fenológico no controle químico de biótipos de azevém resistente e suscetível ao glyphosate e foi conduzido em casa de vegetação, em delineamento inteiramente casualizado com quatro repetições e organizado em esquema fatorial 10x2x2x2. Os herbicidas: clethodim, clodinafop-propargyl, fenoxaprop-p-etyl+clethodim, glyphosate, iodosulfuron-methyl, paraquat, paraquat+diuron, sethoxydim e tepraloxydim foram aplicados em biótipos de azevém resistente e suscetível ao glyphosate sob temperaturas do ar de 20-22 ºC e 30-34 ºC no momento da aplicação e nos estádios de 3-4 folhas e florescimento. O controle dos biótipos foi avaliado aos 7, 14, 21 e 28 dias após a aplicação dos tratamentos, atribuindo-se o percentual de 0 a 100 que correspondeu à ausência de injúria e morte das plantas, respectivamente. A estatura de planta e a massa seca da parte aérea foram determinadas após a última avaliação de controle. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey (p≤0,05). Paraquat e paraquat+diuron controlaram azevém, independente de biótipo, estádio e temperatura de aplicação. Os demais herbicidas controlaram azevém no estádio de 3-4 folhas quando aplicados à 20-22 ºC, independente do biótipo. Herbicidas aplicados a 30-34 ºC não foram eficazes no controle do biótipo resistente em estádio inicial. No florescimento, tepraloxydim e fenoxaprop-p-ethyl+clethodim proporcionaram maior controle do biótipo resistente quando aplicado em temperatura de 30-34 °C. O segundo experimento teve o objetivo de identificar herbicidas alternativos para o controle de buva resistente ao glyphosate, bem como a influência do estádio de desenvolvimento no controle. O mesmo foi conduzido em pomar de maçã, em uma área com histórico de falha de controle de buva com glyphosate. O delineamento foi em blocos casualizados com quatro repetições e organizado em esquema fatorial 5x2, sendo que os herbicidas amônio glufosinato, bentazon, diquat, glyphosate e glyphosate+saflufenacil foram aplicados em buva no estádio de pré-florescimento e em plantas rebrotadas, 15 dias após o corte das mesmas. O controle foi avaliado aos 7, 14, 21 e 28 dias após a aplicação dos tratamentos, atribuindo-se percentual de 0 a 100, correspondente a ausência de injúria e morte das plantas, respectivamente. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey (p≤0,05). Os herbicidas, bentazon, diquat, e glyphosate+saflufenacil não foram eficientes no controle de buva em pré-florescimento; amônio glufosinato mostrou-se uma alternativa viável para o controle de buva em estádios avançados. Com exceção de glyphosate, todos os demais herbicidas controlaram biótipos de buva rebrotada em pomar de maçã

Submitted by BRUNA BARBOZA MARCHESI null (brumarchesi@hotmail.com) on 2016-03-16T17:25:35Z No. of bitstreams: 1 Versão FINAL_Bruna Marchesi.pdf: 2441821 bytes, checksum: 291ac40bb91fa79ae6cb35e82b758c16 (MD5) / Approved for entry into archive by Sandra Manzano de Almeida (smanzano@marilia.unesp.br) on 2016-03-16T17:57:19Z (GMT) No. of bitstreams: 1 marchesi_bb_me_bot.pdf: 2441821 bytes, checksum: 291ac40bb91fa79ae6cb35e82b758c16 (MD5) / Made available in DSpace on 2016-03-16T17:57:19Z (GMT). No. of bitstreams: 1 marchesi_bb_me_bot.pdf: 2441821 bytes, checksum: 291ac40bb91fa79ae6cb35e82b758c16 (MD5) Previous issue date: 2016-01-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Com o objetivo de avaliar os efeitos de formulações e de intervalos sem chuva três experimentos foram conduzidos afim de se obter informações sobre a deposição, absorção, translocação e eficácia dos herbicidas 2,4-D e glyphosate, isolados e em mistura, em plantas de Conyza canadensis. Todos os estudos foram realizados em casa-de-vegetação em delineamento inteiramente casualizado e em esquema fatorial, com 6 herbicidas (780 g e.a. ha-1 do herbicida EnlistTM; 780 + 820 g e.a. ha-1 da mistura formulada EnlistDuoTM; 780 g e.a. ha-1 de DMA 806 BR; 820 g e.a. ha-1 de Glizmax®Prime; 780 + 820 g e.a. ha-1 da mistura dos herbicidas DMA 806 BR + Glizmax®Prime e 780 + 820 g e.a. ha-1 da mistura de EnlistTM + Glizmax®Prime). Para o estudo de absorção o fatorial foi 6X4, com os 6 herbicidas e 4 intervalos de lavagem, com 5 repetições; para os de deposição e translocação o fatorial foi 6X2, sendo os 6 herbicidas e 2 regiões (ápice e base), com 6 repetições; e para o de eficácia, 6X5, os 6 herbicidas e 5 intervalos de chuva, com 4 repetições. No estudo de absorção foram quantificados os teores dos herbicidas internos e externos às plantas. Nos de deposição e translocação a quantificação dos herbicidas internos às plantas foi realizada para ambos, sendo que no de translocação a quantificação foi realizada aos 2 e 4 dias após a aplicação (DAA). No de eficácia foi realizada a avaliação visual de fitointoxicação aos 7, 14, 21 e 28 DAA e a massa seca aos 28 DAA. A mistura de 2,4-D e glyphosate, sendo ela formulada ou em tanque, aumentou a absorção e a eficácia do 2,4-D no controle de Conyza canadensis. A absorção de 2,4-D foi contínua ao longo das primeiras 24 horas com aumento dos teores internos e da porcentagem de controle com o avanço dos intervalos sem chuva ou lavagem. As folhas da base de Conyza canadensis receberam as maiores deposições de 2,4-D e glyphosate, sendo as principais responsáveis pela absorção dos herbicidas. A translocação do 2,4-D e do glyphosate é muito mais intensa no sentido base-ápice do que no sentido inverso. As maiores deposições nas folhas da base associada à maior translocação da base para o ápice contribuem para ação sistêmica desses herbicidas. / With the objective to evaluate the effects of formulations and rainless intervals three experimentes were done in order to obtain information about deposition, absorption, translocation and efficacy of the herbicides 2,4-D and glyphosate, alone or in mixture, in Conyza canadensis plants. All studies were performed in green house in a completely randomized design and in a factorial with 6 herbicides (780 g a.i. ha-1 of the herbicide EnlistTM; 780 + 820 g a.i. ha-1 of the formulated mixture EnlistDuoTM; 780 g a.i. ha-1 of DMA 806 BR; 820 g a.i. ha-1 of Glizmax®Prime; 780 + 820 g a.i. ha-1 of the herbicides mixtures DMA 806 BR + Glizmax®Prime and 780 + 820 g a.i. ha-1 of the mixture EnlistTM + Glizmax®Prime). To the absorption study the fatorial was 6X4, with 6 herbicides and 4 washing intervals, with 5 repititions; to the deposition and translocation study, the factorial was 6x2, with 6 herbicides and 2 regions (apex and base), with 6 repetitions; and to the efficacy study, 6X5, with the 6 herbicides and 5 rain intervals, with 4 repetitions. In the absorption study were quantified the levels of internal and external herbicides to plants. In the deposition and translocation, quantifying the internal herbicides to plants was conducted for both and to translocation the quantification performed at 2 and 4 days after application (DAA). For the efficacy study it was conducted a visual evaluation of injury at 7, 14, 21 and 28 DAA and dry mass at 28 DAA. The mixture of 2,4-D and glyphosate, formulated or in a tank mix, increased the absorption and the efficacy of 2,4-D in control of Conyza canadensis. The 2,4-D absorption was uniform throughout the first 24 hours with increasing internal levels and the percentage of control with the advance of intervals without rain or washing. The base leaves of Conyza canadensis received the biggest deposition of 2,4-D and glyphosate, mainly responsible for the absorption of herbicides. The translocation of 2,4-D and glyphosate is much more intense towards base-apex than in the reverse. The biggest depositons in the base leaves associated with higher translocation from base to apex contribute to systemic action of these herbicides.

Thesis (MScAgric)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Conyza bonariensis (flaxleaf fleabane) was reported for the first time, as a weed in California in 1893-1896. The first report of the occurrence of this weed in South Africa was made in May 1895 in Franschoek, South Africa. Paraquat resistance in C. bonariensis was first reported in the 1970s and early 1980s when resistance was observed from vineyards and citrus plantations in Egypt. More recently a report of herbicide resistance in South Africa was made in January 2003 when resistance occurred in C. bonariensis in the Breede Valley, South Africa. The resistance was to glyphosate, but recently reports of resistance to glyphosate and paraquat were received. C. bonariensis seeds were found to be positively photoblastic and germinated only under unfiltered white light and red light whilst no germination occurred under far-red light and in the dark. The optimum temperature range for C. bonariensis seed was found to be between 15 and 30°C, with no germination occurring at 0-5°C and at 35- 40°C. Optimum germination occurred at the soil surface. No germination occurred at depths of 2 cm and deeper. Although the optimum temperature range was found to be the same for the different biotypes tested. However, germination was highest in the susceptible biotype. Since farmers first reported paraquat and glyphosate resistance in C. bonariensis in the Breede Valley, South Africa, reports of resistance increase every year. Seed collected from populations suspected of being resistant to paraquat and glyphosate were obtained from the Breede Valley and screened for resistance. To determine the easiest, quickest, and most effective method to screen for paraquat and glyphosate resistance, two tests were evaluated viz. the petri dish assay method and the whoIeplant dose-response method. Both screening methods identified paraquat and glyphosate resistant biotypes. The petri dish assay method was found to be a more rapid method of screening for resistance in C. bonariensis. During this study it was found that both paraquat and glyphosate resistance does occur in the Breede Valley. The effect of growth stage on the level of herbicide resistance in C. bonariensis was tested. Herbicides other than paraquat and glyphosate were tested to determine if they could be used to control resistant C. bonariensis seedlings. The alternative herbicides tested included MCPA and Sorgomil Gold 600. The four herbicides were sprayed at different leaf stages. During the study it was found that growth stage does play an important role in the level of herbicide resistance. It was found that the control of different herbicides decreased with an increase in growth stage. The different herbicides showed varying levels of control depending on growth stage and resistant profile. Overall MCPA gave the best control at all leaf stages tested. What is gratifying was the finding that every biotype tested could be controlled by at least one of the treatments applied. This means that the producer using the most appropriate herbicide applied at the optimum application stage will be able to control most if not all the resistant populations of C. bonariensis that occur in the Western Cape. / AFRIKAANSE OPSOMMING: Conyza bonariensis (Kleinskraalhans) is vir die eerste keer as 'n onkruid gerapporteer in Kalifornia in 1893-1896. Die eerste waarneming van hierdie onkruid in Suid-Afrika is gemaak in Mei 189S in Franschoek. Parakwat weerstandbiedendheid in C. bonariensis is die eerste maal in die 1970s en vroeë 1980s waargeneem, toe weerstandbiedendheid opgemerk is in wingerde en sitrus plantasies in Egipte. Meer onlangs is 'n geval van onkruiddoder weerstandbiedendheid in Suid-Afrika aangemeld in Januarie 2003, toe 'n biotipe van C. bonariensis in die Breede Vallei weerstand-biedendheid getoon het teen 'n onkruiddoder. Die weerstand was teen glifosaat, maar onlangse berigte van weerstandbiedendheid teen glifosaat sowel as parakwat is ontvang. Daar is gevind dat die saadjies van C. bonariensis positief fotoblasties is en slegs ontkiem onder ongefiltreerde wit- en rooi lig, terwyl geen ontkieming voorkom onder ver-rooi lig en in die donker nie. Die optimum temperatuurreeks vir C. bonariensis saad is tussen IS en 30°C, met geen ontkieming wat by O-SoCen by 3S-40°C voorkom nie. Optimum ontkieming kom voor op die grondoppervlak. Geen ontkieming kom by dieptes van 2 cm of dieper voor nie. Alhoewel die optimum temperatuurreeks dieselfde is vir die verskillende biotipes wat getoets is, is daar tog 'n verskil in die persentasie ontkieming tussen die biotipes met die beste ontieming by die sensitiewe biotipe. Sedert boere die eerste geval van parakwat en glifosaat weerstandbiedendheid in C. bonariensis in die Breede Vallei, Suid-Afrika gerapporteer het, word meer gevalle van weerstandbiedendheid jaarliks aangemeld. Saad van populasies wat vermoedelik parakwat en glifosaat weerstandbiedend is, is in die Breede Vallei versamel en getoets vir weerstandbiedendheid. Om die maklikste, vinnigste en mees effektiewe metode van weerstandbiedendheidstoetsing te vind, is twee verskillende metodes van toetsing, naamlik die petribakkietoets en die heel plant dosis respons metode gebruik. Beide metodes van toetsing het parakwat en glifosaat weerstandbiedende biotipes geïdentifiseer. Daar is gevind dat die petri bakkie metode 'n vinniger manier van toetsing vir weerstandbiedendheid is. Die studie het ook bewys dat parakwat en glifosaat weerstandbiedendheid wel in die Breede Vallei, Suid-Afrika voorkom. Die effek van groeistadium op die vlak van onkruiddoder weerstandbiedendheid in C. bonariensis is ook tydens die studie getoets. Ander onkruiddoders buiten parakwat en glifosaat is getoets om te bepaal of hulle gebruik kan word vir die effektiewe beheer van weerstandbiedende C. bonariensis saailinge. Die alternatiewe onkruiddoders wat getoets is, was MCPA en Sorgomil Gold 600. Die vier onkruiddoders is gespuit by verskillende blaarstadiums. Gedurende die studie is daar gevind dat groeistadium wel 'n belangrike rol speel in die vlak van onkruiddoder weerstandbiedendheid. Die persentasie beheer van verskillende onkruiddoders neem af met 'n toename in die groeistadium. Die verskillende onkruiddoders se beheer het gewissel afhangend van weerstandbiedendheid en groeistadium. MCPA het die beste beheer by alle blaarstadiums wat getoets is getoon. Daar is ook gevind dat een of die ander van die onkruiddoders wat getoets is, gebruik kan word vir die suksesvolle beheer van onkruiddoder weerstandbiedendheid in elke biotipe wat getoets is. Dit beteken dat 'n produsent wat die korrekte onkruiddoder op die korrekte groeistadium toedien, in staat sal wees om die meeste, indien nie alle weestandbiedende C. bonariensis populasies wat in die Wes Kaap voorkom, te beheer.