Competition studies with soybeans, Glycine max (L.) Merr. "Bragg." and sicklepod, Cassia obtusifolia L., were conducted at the Agricultural Research and Education Center of the University of Florida in Quincy, Florida. Two field experiments were established, one on May 22, 1975. and the other four weeks later, on June 19, 1975, to determine the competitive effects of various sicklepod densities and the influences of soybean row distances on weed dry matter, soybear plant characteristics, yield components and seed yield, and on soil nutrient content. Control, low, medium, and high sicklepod densities in the first experiment were O, 25,000, 53,000, and 77,000 p1ants/ha, respectively; while the second experiment presented control, low, medium, and high sicklepod densities of O, 36,000, 68,000, and 122,000 plants/ha, respectively. Three soybean row distance treatments were tested using a constant pattern of 90-, 60-, and 45-cm widths throughout the growing season. Three other treatments, evaluated in a variable patern, were initially seeded in 30-cm row widths. Five weeks after planting, an appropriate number of soybean rows were harvested from the 30"cm pattern to establish row distances of 90, 60, and 30-60 cm for the remainder of the season. ln the greenhouse a test was conducted to evaluate the effects af those variables on seed germination and seedling vigor for the next soybean generation. As a result of full-season sicklepod competition, soybean plants were less branched, set fewer leaves, and presented thinner stems as compared to the control. However, height of soybean plants was not affected by the presence of sicklepod. ln one of the two experiments, number of nodes decreased for soybeans under weed campetition. The yield components--number of pods; number of seeds, and seed yield per soybean plant--were all similarly reduced due to weed competition. Seeds per pod were decreased to a lesser extent. Soybean seed yields per unit area were significantly diminished by increasing levels af sicklepod ínfestation. While the control produced 3120 kg/ha, the sicklepod densities of 25,000, 53,000, and 77,000 plants/ha reduced seed yíelds 47, 65, and 73%, respectively. As soybean row distances decreased, number of branches, number of leaves, and stem diameter of soybeans decreased. However, the height of soybean plants increased with narrwing of row width. The components of seed yield--number of pods, number of seeds, and seed yield per soybean plant--diminished as row spacing was reduced. Maximum difference between row distances for these attributes was attained for soybean plants under weed-free conditions. Generally, as row width decreased, soybean seed yield per unit area increased. Specifically, soybear.s in 90-cm rows, either in constant or variable row pattern, yielded less than soybeans in 60- and 30-60-cm rows in the variable pattern. Soil contents of phosphorus, potassium, calcium, and magnesium were not affected by the various levels of sicklepod and soybean populalions. Neither the sicklepod densities nor the soybean row distances influenced seed germination and seedling vigor in the next soybean generation. Sicklepod was a strong competitor with soybeans at all density ranges investigated. Because sicklepod grows taller than soybeans during the reproductive stages of the crop, limited success can be reached by varying row spacing alone. However, this practice is considered an integral measure to complement other methods of sicklepod control. Compared to constant rows, the soybean cropping system using variable row spacings presents the choice of planting soybeans at close row spacings to provide early competition with weeds and the possibility of obtaining a forage crop after the first month of growth, without any decreases on the final seed yields.

Competition studies with soybeans, Glycine max (L.) Merr. "Bragg." and sicklepod, Cassia obtusifolia L., were conducted at the Agricultural Research and Education Center of the University of Florida in Quincy, Florida. Two field experiments were established, one on May 22, 1975. and the other four weeks later, on June 19, 1975, to determine the competitive effects of various sicklepod densities and the influences of soybean row distances on weed dry matter, soybear plant characteristics, yield components and seed yield, and on soil nutrient content. Control, low, medium, and high sicklepod densities in the first experiment were O, 25,000, 53,000, and 77,000 p1ants/ha, respectively; while the second experiment presented control, low, medium, and high sicklepod densities of O, 36,000, 68,000, and 122,000 plants/ha, respectively. Three soybean row distance treatments were tested using a constant pattern of 90-, 60-, and 45-cm widths throughout the growing season. Three other treatments, evaluated in a variable patern, were initially seeded in 30-cm row widths. Five weeks after planting, an appropriate number of soybean rows were harvested from the 30"cm pattern to establish row distances of 90, 60, and 30-60 cm for the remainder of the season. ln the greenhouse a test was conducted to evaluate the effects af those variables on seed germination and seedling vigor for the next soybean generation. As a result of full-season sicklepod competition, soybean plants were less branched, set fewer leaves, and presented thinner stems as compared to the control. However, height of soybean plants was not affected by the presence of sicklepod. ln one of the two experiments, number of nodes decreased for soybeans under weed campetition. The yield components--number of pods; number of seeds, and seed yield per soybean plant--were all similarly reduced due to weed competition. Seeds per pod were decreased to a lesser extent. Soybean seed yields per unit area were significantly diminished by increasing levels af sicklepod ínfestation. While the control produced 3120 kg/ha, the sicklepod densities of 25,000, 53,000, and 77,000 plants/ha reduced seed yíelds 47, 65, and 73%, respectively. As soybean row distances decreased, number of branches, number of leaves, and stem diameter of soybeans decreased. However, the height of soybean plants increased with narrwing of row width. The components of seed yield--number of pods, number of seeds, and seed yield per soybean plant--diminished as row spacing was reduced. Maximum difference between row distances for these attributes was attained for soybean plants under weed-free conditions. Generally, as row width decreased, soybean seed yield per unit area increased. Specifically, soybear.s in 90-cm rows, either in constant or variable row pattern, yielded less than soybeans in 60- and 30-60-cm rows in the variable pattern. Soil contents of phosphorus, potassium, calcium, and magnesium were not affected by the various levels of sicklepod and soybean populalions. Neither the sicklepod densities nor the soybean row distances influenced seed germination and seedling vigor in the next soybean generation. Sicklepod was a strong competitor with soybeans at all density ranges investigated. Because sicklepod grows taller than soybeans during the reproductive stages of the crop, limited success can be reached by varying row spacing alone. However, this practice is considered an integral measure to complement other methods of sicklepod control. Compared to constant rows, the soybean cropping system using variable row spacings presents the choice of planting soybeans at close row spacings to provide early competition with weeds and the possibility of obtaining a forage crop after the first month of growth, without any decreases on the final seed yields.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-30T12:37:41Z No. of bitstreams: 1 danielademeloaguiar.pdf: 1617352 bytes, checksum: 517dd7d07597e472de5e2a93de909b1e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-02T11:58:24Z (GMT) No. of bitstreams: 1 danielademeloaguiar.pdf: 1617352 bytes, checksum: 517dd7d07597e472de5e2a93de909b1e (MD5) / Made available in DSpace on 2016-07-02T11:58:24Z (GMT). No. of bitstreams: 1 danielademeloaguiar.pdf: 1617352 bytes, checksum: 517dd7d07597e472de5e2a93de909b1e (MD5) Previous issue date: 2012-02-23 / As pastagens representam recursos de importância para a atividade pecuária brasileira, tendo a cigarrinha como sua principal praga devido aos danos provocados à forrageira na estação quente e chuvosa, época que o gado deveria se recuperar da seca infringida às pastagens nos meses anteriores. Para a redução do uso de inseticidas químicos é necessário desenvolver métodos de controle alternativos. Neste cenário o controle cultural recebe destaque e a adubação balanceada constitui prática que melhora a condição nutricional do solo, com consequente suplementação no desenvolvimento da forrageira e possibilidade de indução de resistência de plantas. Portanto, com o objetivo de verificar a promoção de antibiose e tolerância, foram avaliados os efeitos da aplicação de diferentes doses de nitrogênio, fósforo e potássio (NPK) em plantas de Brachiaria ruziziensis (Germain & Evrard) expostas à Mahanarva spectabilis (Distant, 1909) sob condição de casa-de-vegetação. Para a realização dos três experimentos foram utilizados ovos, ninfas e adultos de cigarrinhas e três diferentes doses de NPK. Ovos foram depositados ao solo em vasos contendo braquiária e após 32 dias avaliou-se a sobrevivência ninfal. Em outra etapa foram colocadas ninfas de cigarrinhas na base de plantas de braquiária e após 10 dias avaliaram-se os danos provocados pelas ninfas às plantas, assim como o crescimento, número de perfilhos, rebrota e qualidade bromatológica da forrageira. No terceiro experimento os cercopídeos adultos foram colocados em gaiolas contendo braquiária. Após cinco dias avaliaram-se os danos provocados pelo inseto às plantas e a produção de matéria seca, rebrota e qualidade bromatológica da forrageira. Verificou-se que a adubação não promoveu antibiose; entretanto a aplicação de metade da dose de NPK foi suficiente para diminuir em mais de 20% os danos causados pelo inseto à forrageira, garantir a rebrota em mais de 70% quando houve baixa infestação de ninfas e presença de adultos, proporcionar maior produção de matéria seca, aumentar o numero de perfilhos emitidos e elevar a celulose das plantas, indicando que houve a promoção de tolerância. Desta forma, conclui-se que a adubação constitui alternativa eficaz para diminuir os danos causados pela cigarrinha-das-pastagens. / Pastures represent a resource for Brazilian cattle ranching, with the spittlebug as their main pest because of the damaged caused in the hot and rainy season that cattle should be broken to recover from drought pasture during the months above. To reduce the use of chemical insecticides is necessary to develop alternative control methods. In this scenario receives prominent cultural control and fertilization is balanced practice that improves the nutritional status of soil, resulting in the development of forage supplementation and possible induction of resistance in plants. Therefore, in order to verify the promotion of antibiosis and tolerance, was evaluated the effects of different doses of nitrogen, phosphorus and potassium (NPK) in Brachiaria ruziziensis (Germain & Evrard) exposed to Mahanarva spectabilis (Distant, 1909) on condition of green house. For the realization of three experiments were used eggs, nymphs and adult of spittlebug and three different doses of NPK. Eggs were deposited in the soil in pots containing brachiaria and, after 32 days, were assessed on nymphs. In another stage nymphs were placed at the base of plants of brachiaria and after 10 days evaluated the damage to plants by the nymphs and growth, tiller number, sprouting and chemical quality of forage. In the third experiment cercopidae adults were placed in cages containing Brachiaria. After five days, was evaluated the damage caused by insects to plants and dry matter production, regrowth and chemical quality of forage. It was found that fertilization did not cause antibiosis, however, the application of half dose of NPK was sufficient to decrease by more than 20% damage by insects to forage, to ensure regrowth in more than 70% when there was a low infestation of nymphs and the presence of adults, higher dry matter production, increase the number of tillers and increase cellulose plants, indicating that there was the promotion of tolerance. Thus, it is concluded that fertilization is an effective alternative to reduce the damage caused by spittlebugs.

The blast is the main disease of flooded rice. The integrated management of this disease is based on the adoption of cultural, genetic and chemical strategies of control. The objective of this work was to evaluate the effect of eight chemical control programs of Pyricularia oryzae applied on IRGA 424, IRGA 428, GURI INTA CL, PUITA INTA CL, QM 10 10 CL and INOV CL rice varieties, and 10/30/2013 and 11/26/2013 sowing times. This work was conducted in the 2013/2014-crop season, under field conditions, in lowland area in Sao Sepé, RS, Brazil. The treatments were arranged in a randomized experimental blocks design, in a split plot and five replications. The variables analyzed were AUCPD on the flag leaf and entire plant, panicle blast, yield and the whole grains percentage. The delay in sowing date increased significantly the incidence and severity of the blast in flooded rice. IRGA 424, IRGA 428 and QM 10 10 CL showed resistance to Pyricularia oryzae, while the GURI INTA CL, PUITA INTA CL and INOV CL were susceptible. The addition of Tricyclazole fungicide to Kresoxim-methyl + Epoxiconazole fungicides is critical to the efficient control of Pyricularia oryzae. The applications of fungicides in the R1 + R2 + R4 and R2 + R4 stages are the most effective in the chemical control of rice blast. The integration among cultural, genetic and chemical methods is critical to the efficient management of blast in flooded rice. / A brusone é a principal doença da cultura do arroz irrigado. O manejo integrado desta doença é baseado na adoção de um conjunto de métodos de controle, como o controle cultural, controle genético e o controle químico. O objetivo deste trabalho foi avaliar o efeito de oito programas de controle químico de Pyricularia oryzae, nas cultivares de arroz irrigado IRGA 424, IRGA 428, GURI INTA CL, PUITÁ INTA CL, QM 10 10 CL e INOV CL, nas datas de semeadura de 30/10/2013 e 26/11/2013. O experimento foi conduzido em São Sepé/RS, na safra 2013/14, obedecendo o delineamento experimental de blocos ao acaso, em parcelas subsubdivididas e cinco repetições. As variáveis consideradas foram AACPB na folha bandeira e na planta inteira da cultura do arroz, o percentual de incidência de brusone na base da panícula, a produtividade e o percentual de grãos inteiros. O atraso na época de semeadura aumentou significativamente a incidência e a severidade da brusone na cultura do arroz irrigado. IRGA 424, IRGA 428 e QM 10 10 CL apresentaram resistência à Pyricularia oryzae, enquanto que GURI INTA CL, PUITÀ INTA CL e INOV CL foram suscetíveis. A adição do fungicida Triciclazol aos fungicidas Cresoxim-metilico + Epoxiconazol foi eficiente para controle de Pyricularia oryzae. As aplicações de fungicidas para controle químico da brusone foram mais eficazes quando realizadas nos estádios R1 + R2 + R4 e R2 + R4. A integração entre os métodos cultural, genético e químico foi eficiente para o manejo da brusone na cultura do arroz irrigado.

Three experiments were conducted in 2012, two in the field and one in the greenhouse with the objective of identifying the competitive potential of different wheat cultivars. The field experiments were conducted in Cruz Alta, RS and Vacaria, RS in the absence and presence of competition with ryegrass. In the greenhouse the wheat cultivars were sown in pots to evaluate initial growth. 2013 Cruz Alta, RS two experiments were conducted using contrasting cultivars related to the competitive potential defined in the experiments of 2012. This experiment had the purpose of evaluating the contribution of the competitive potential in chemical control of ryegrass. Five managements of ryegrass, control, weeded, herbicide application iodossulfuron-methyl at a dose of 5 g ha-1 at the beginning of tillering, herbicide application 15 days and 30 days after the start of tillering were used. Plant characteristics such as plant height, dry matter of shoots, ground cover, potential competitive ability and yield losses due to the competition, in addition to the suppression ability of the ryegrass indicate that the cultivar BRS 327 has high competitive potential with ryegrass and the variety OR 1 has the lowest competitive potential among the tested cultivars. The higher competitive potential of the cultivar BRS327 related to OR1, did not serve as an auxiliary tool in the management of ryegrass. The higher competitive potential of the cultivar Fundacep 47 compared to Fundacep 30 served as an auxiliary tool in the management of ryegrass. / Foram conduzidos três experimentos no ano de 2012, dois a campo e um em casa de vegetação com o objetivo de identificar o potencial competitivo de diferentes cultivares de trigo. Os experimentos a campo foram conduzidos em Cruz Alta, RS e Vacaria, RS, na ausência e presença da competição com o azevém. Em casa de vegetação os cultivares de trigo foram semeados em vasos para avaliar o seu crescimento inicial. No ano de 2013, em Cruz Alta, RS, foram conduzidos dois experimentos utilizando cultivares contrastantes quanto ao potencial competitivo definidos nos experimentos de 2012. Este experimento teve o objetivo de avaliar a contribuição do potencial competitivo no controle químico do azevém. Foram utilizados cinco manejos de azevém, testemunha sem controle, testemunha capinada, aplicação de herbicida iodossulfuron-methyl na dose de 5 g ha-1 no início do afilhamento, aplicação do herbicida 15 dias e 30 dias após o início do afilhamento. As características das plantas, como estatura, matéria seca da parte aérea, cobertura do solo, habilidade competitiva potencial e perdas na produtividade em função da competição, além da capacidade de supressão do azevém indicam que o cultivar BRS 327 tem alto potencial competitivo com o azevém e que o cultivar OR 1 tem o menor potencial competitivo entre os cultivares testados. O maior potencial competitivo do cultivar BRS327 em relação a OR1, não serviu de ferramenta auxiliar no manejo do azevém. O maior potencial competitivo do cultivar Fundacep 47 em relação ao Fundacep 30 serviu como ferramenta auxiliar no manejo do azevém.

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No. of bitstreams: 1 Tese - Odiluza Maria Saldanha de Oliveira.pdf: 778336 bytes, checksum: d9880fba205424a41ded1fcbc88afd94 (MD5) Previous issue date: 2014-02-24 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / The weed interferencein in crop areas of cowpea reduces their yield of cowpea at 90%, varying in intensity that depends on factors related to weeds community Among the options for weed management, is the cultural method in which the use of cultivars with high competitive ability coupled with narrow row spacing provides conditions for the culture to be established effectively on the soil surface. However, in order not to compromise the yield of cowpea proper use of plant density, which depends on the intrinsic characteristics of the cultivar as size, growth habit, plant architecture and management system used is required. Analysis of the correlation coefficient is a complementary tool to assess the contribution of each factor in the productivity of cowpea under this stress situation. The objective of this experiment was to evaluate the competitiveness of cowpea cultivars at different spacings in upland soil in the state of Amazonas. The experimental design was a randomized complete block with three replications, arranged in sub-subplots. In the plots was used the row spacings of 0,50 m (recommended); 0,40 m and 0,30 m; in the subplots two system of control of weeds, and in sub-subplots cultivars of cowpea caupi BR8 Caldeirão, IPEAN V69, BRS Guariba e BR 17 Gurguéia. Were evaluated: leaf area, dry weight of leaves and of the aerial part, size of pods, number of pods per plant, number of pods, number of seeds per pod, harvest index, one hundred seed weight and yield, leaf area ratio, specific leaf area and leaf area index. Weed evaluation was carried at intervals of 7 days with the use of a square of 0.25 m2 that was carried out with in the useful area subplot for identification, counting and collecting weeds bounded by the square to verify the dry weight of shoots. The phytosociological parameters of frequencies, densities and abundances relative and absolute indices and importance value of species were calculated. It was used the path analysis to decompose the different correlations and their direct and indirect effects. The cv. BR8 Caldeirão had the highest values for measured characteristics followed in order of decreasing values for BRS Guariba, BR 17 Gurguéia IPEAN V69 viii respectively. The yield of cvs. showed a similar trend to the other variables analyzed. The spacing between rows of plants was not significant for productivity, but the cultivars differed from each other between different linear arrangements. The weeds highest IVI in row spacing of 0,5 e 0,4 m were Croton glandulosus and Mimosa pudica for 0,3 m. The most important species for the quantity cvs. were Paspalum multicaule for BR8 Caldeirão, Elephantopus mollis to BRS Guariba and Cleome affinis to IPEAN V69 and BR 17 Gurguéia. IPEAN V69 was the most susceptible to weed competition for dry matter production.The number of pods per plant and leaf area were the features most correlated with productivity. These features showed to be efficient for indirect selection to obtain genetic gains on the productivity of grains. Moreover, these features are also important on the indirect effects of the number of seeds per pod, plant height and dry weight of the aerial parts. / Plantas daninhas em área de cultivo de feijão-caupi causam interferência que pode reduzir a obtenção de grãos em até 90%, o que dependerá de fatores ligados à comunidade infestante. Dentre as opções de manejo das plantas daninhas, encontra-se o método cultural em que o uso de cultivares com elevada capacidade competitiva aliado à redução do espaçamento entrelinhas fornece condições para que a cultura se estabeleça eficazmente na superfície do solo. Entretanto, para não comprometer a produtividade da cultura de feijão-caupi é necessária a utilização adequada da densidade das plantas, o que depende das características intrínsecas da cultivar como porte, hábito de crescimento, arquitetura de planta e do sistema de manejo utilizado. Para quantificar a contribuição de cada fator na produtividade do feijão-caupi nesta situação de estresse competitivo é realizada complementarmente a análise de coeficiente de correlação. O objetivo deste experimento foi avaliar a capacidade competitiva de cultivares de feijão-caupi em diferentes espaçamentos em solo de terra firme no estado do Amazonas. O experimento foi delineado em parcelas sub-subdivididas em blocos casualizados com três repetições. Na parcela foram usados os espaçamentos de 0,50 m (recomendado); 0,40 m e 0,30 m; nas subparcelas os dois sistemas de manejo das plantas daninhas com e sem capina e nas sub-subparcelas as cultivares de feijão-caupi IPEAN V69, BR8 Caldeirão; BRS Guariba; BR 17 Gurguéia. Foram determinadas a área foliar, massa seca das folhas e da parte aérea, tamanho das vagens, número de vagens por planta, número total de vagens, número de sementes por vagem, índice de colheita, peso de cem sementes e produtividade, razão da área foliar, área foliar especifica e índice de área foliar. A avaliação da infestação de plantas daninhas foi realizada em intervalos de 7 dias com a utilização de um quadrado de 0,25 m2, lançado aleatoriamente na área útil da sub-subparcela não-capinada para identificação, contagem e coleta das plantas daninhas delimitadas pelo quadrado para verificar a massa seca da parte aérea. Foram calculados os parâmetros fitossociológicos das espécies. Estimou-se as vi correlações genotípicas entre pares de caracteres e seus efeitos diretos e indiretos considerando os componentes de produção. A cv. BR8 Caldeirão apresentou os maiores valores para as características avaliadas, seguida respectivamente em ordem decrescente de valores por BRS Guariba, BR 17 Gurguéia e IPEAN V69. A produtividade das cvs. seguiu tendência similar às demais variáveis analisadas. Os espaçamentos entre linhas não foram significativos para a produtividade, mas as cultivares diferiram entre si dentro de cada espaçamento. As plantas daninhas com maior IVI foram Croton glandulosus nos espaçamentos de 0,5 e 0,4 m, Mimosa pudica para 0,3m e Paspalum multicaule para BR8 Caldeirão, Elephantopus mollis para BRS Guariba e Cleome affinis para IPEAN V69 e BR 17 Gurguéia. A cultivar IPEAN V69 foi a mais susceptível aos problemas de competição com a flora infestante quanto à produção de matéria seca. O número de vagens.planta-1 e a área foliar foram os caracteres mais correlacionados com a produtividade e se mostram eficientes em praticar-se seleção indireta, com o intuito de obter ganhos genéticos sobre o rendimento de grãos. A cultivar BR8 Caldeirão foi a que demonstrou maior habilidade competitiva com base nos parâmetros avaliados.

O cancro cítrico, causado pela bactéria Xanthomonas axonopodis pv. citri, é uma das doenças mais importantes da citricultura. O estudo do efeito de medidas alternativas de controle para o manejo desta doença assume grande importância tanto para áreas citrícolas onde a erradicação de plantas não é a principal medida de controle do cancro cítrico, como no Estado do Paraná, como para regiões onde a prática da erradicação vem sendo adotada como principal medida de controle da doença, como no Estado de São Paulo. Instalado em pomar citrícola do município de Ourizona, na região Noroeste do Estado do Paraná, este trabalho buscou estudar o progresso dessa importante doença em campo sob condições de proteção química das plantas, utilizando produto cúprico; e cultural, por meio de quebra-vento. Além disso, importantes informações relacionadas ao efeito de cada tratamento sobre a produção das plantas de laranja ‘Pêra’ também foram obtidas. Enquanto a aplicação de cobre apresentou efeito significativo na redução dos níveis de cancro cítrico, o emprego de quebra-vento pouco ou nada contribuiu para o controle da doença. Após 29 avaliações mensais, plantas submetidas à aplicação de bactericida cúprico apresentaram valores médios de AUDPC* de incidência da doença nas folhas de cerca de 20 %, nível 44 % inferior ao observado para as plantas não protegidas quimicamente. O mesmo comportamento foi observado para a severidade da doença. Após 18 avaliações mensais foi possível observar que plantas submetidas à aplicação de produto cúprico apresentaram em média folhas com níveis de AUDPC* de severidade 37 % menores do que plantas não protegidas quimicamente. Em 2004, quando os níveis da doença foram relativamente elevados, plantas submetidas ao controle químico apresentaram produção 54 % superior àquelas não tratadas. Em 2005, quando os níveis de cancro foram menores, não foi observada diferença na produtividade entre os tratamentos. Nas duas safras, plantas tratadas com bactericida apresentaram menor incidência da doença em frutos e maior proporção de frutos colhidos em relação a carga total da planta (colhidos + caídos). Dos modelos testados, o logístico foi o mais adequado para descrever o progresso temporal do cancro cítrico nos dois anos estudados para todos os tratamentos. Nas duas safras estudadas a proporção de frutos colhidos foi a variável que apresentou função de dano com maior coeficiente de determinação (R2) quando relacionada aos níveis de incidência e severidade de cancro cítrico observados. / Citrus canker, caused by Xanthomonas axonopodis pv. citri, is one of the most important diseases to citrus production. The effect of alternative measures of citrus canker control is very important to areas where plant eradication is the most important measure of control, as in Sao Paulo State, as well as to areas where eradication is not a major component of canker control, as in Parana State. This work aimed to study the progress of citrus canker in field conditions under chemical control, by using copper sprays; and cultural control, by using windbreak. Field plots were installed in a citrus orchard of ‘Pêra’ sweet orange located in Ourizona county, northwest of Parana State, Brazil. Information regarding the effect of each treatment alone or in combination was assessed. Whereas copper sprays showed significant effect on reducing citrus canker levels, windbreak did not contribute significantly to disease control. After 29 monthly assessments, plants submitted to copper sprays showed values of AUDPC* of citrus canker incidence near to 20 %. This disease level was 44 % lower than that observed to plants not protected with copper compound. The same pattern was observed to disease severity. After 18 monthly assessments, plants sprayed with copper showed values of AUDPC* of disease severity 37 % lower than that observed to plants of the check plots. In 2004, when the citrus canker level was higher, plants treated with copper yielded 54 % more than that not sprayed. In 2005, when the citrus canker level was lower, no significant difference was observed between treatments. In both seasons, plants sprayed with copper showed lower citrus canker incidence on fruits and higher rate of harvested fruits. Among the temporal models tested, the logistic was the most appropriate to describe citrus canker incidence over time in both years studied to all treatments. In both harvests the rate of harvested fruits was the variable that showed the higher coefficient of determination (R2) when related to citrus canker incidence and severity levels.

Vinte e um isolados de Xanthomonas campestris pv. citri (Xcc), provenientes de cinco municípios do RS, foram cultivados em meio de cultura CYE (casitone, 1; extrato de levedura, 0,35; glicerol, 2; ágar, 15 g/1), com zero, 16, 32, 40, 48 , 64 , 80 , 96 , 112 e 128x10-2 nM de CuS04. A concentração mínima inibitória (CMI) de CuS04 foi de 40x10-2 nM para todos os isolados. O clone pCuR2.A de X. campestris pv. vesicatoria, associado com resistência ao cobre, foi utilizado como sonda para detecção de homologia com o ADN total de Xcc. Não houve hibridização com o ADN total de nenhum dos 21 isolados. Quando o ADN plasmidial de 16 isolados foi digerido com as enzimas de restrição HindIII e BamHI, fragmentos, variando de 9 a 10 kb e 4 a 5 kb, respectivamente, foram detectados com maior frequência. Os plasmídeos apresentaram grande polimorfismo, porém a análise de grupos hierárquicos indicou a formação de pelo menos três grupos distintos. O uso de perfis de restrição para identificação de Xcc dependerá da escolha de perfis realmente representativos de cada grupo para viabilizar comparações. A relação entre a virulência de Xcc com o perfil de restrição plasmidial não foi confirmada. / Twenty one isolates of Xanthomonas campestris pv. citri (Xcc ), from five counties of RS, were grown on CYE (casitone, 1; yeast extract, 0. 35; glycerol, 2; agar 15 g per liter ) culture amended with zero, 16, 32, 40, 48, 64, 80, 96, 112 and 128x10-2 mM CuS04. The CuS04 minimum inhibitory concentration (CMI) was 40x10-2 mM to all isolates . The pCuR2.A clone of X. campestris pv. vesicatoria, associated with copper resistance, was used as a probe to detect homology with total DNA of Xcc. No hibridization with DNA of the 21 isolates was found. When hybridization with total DNA of 16 isolates was digested with Hind III and Bam HI restriction enzymes, fragments, ranging from 9 to 10 kb and 4 to 5 kb, respectively, were detected more frequently. There was great polymorphism among plasmids, and the a nalysis of hierarquical groups showed at least three distinct groups. The use of DNA restriction profile to ide ntify Xcc depends on a representative profile of each group to allow comparinsons. The relationship betweem virulence of Xcc and the plasmid DNA restriction profile was not confirmed.

Vinte e um isolados de Xanthomonas campestris pv. citri (Xcc), provenientes de cinco municípios do RS, foram cultivados em meio de cultura CYE (casitone, 1; extrato de levedura, 0,35; glicerol, 2; ágar, 15 g/1), com zero, 16, 32, 40, 48 , 64 , 80 , 96 , 112 e 128x10-2 nM de CuS04. A concentração mínima inibitória (CMI) de CuS04 foi de 40x10-2 nM para todos os isolados. O clone pCuR2.A de X. campestris pv. vesicatoria, associado com resistência ao cobre, foi utilizado como sonda para detecção de homologia com o ADN total de Xcc. Não houve hibridização com o ADN total de nenhum dos 21 isolados. Quando o ADN plasmidial de 16 isolados foi digerido com as enzimas de restrição HindIII e BamHI, fragmentos, variando de 9 a 10 kb e 4 a 5 kb, respectivamente, foram detectados com maior frequência. Os plasmídeos apresentaram grande polimorfismo, porém a análise de grupos hierárquicos indicou a formação de pelo menos três grupos distintos. O uso de perfis de restrição para identificação de Xcc dependerá da escolha de perfis realmente representativos de cada grupo para viabilizar comparações. A relação entre a virulência de Xcc com o perfil de restrição plasmidial não foi confirmada. / Twenty one isolates of Xanthomonas campestris pv. citri (Xcc ), from five counties of RS, were grown on CYE (casitone, 1; yeast extract, 0. 35; glycerol, 2; agar 15 g per liter ) culture amended with zero, 16, 32, 40, 48, 64, 80, 96, 112 and 128x10-2 mM CuS04. The CuS04 minimum inhibitory concentration (CMI) was 40x10-2 mM to all isolates . The pCuR2.A clone of X. campestris pv. vesicatoria, associated with copper resistance, was used as a probe to detect homology with total DNA of Xcc. No hibridization with DNA of the 21 isolates was found. When hybridization with total DNA of 16 isolates was digested with Hind III and Bam HI restriction enzymes, fragments, ranging from 9 to 10 kb and 4 to 5 kb, respectively, were detected more frequently. There was great polymorphism among plasmids, and the a nalysis of hierarquical groups showed at least three distinct groups. The use of DNA restriction profile to ide ntify Xcc depends on a representative profile of each group to allow comparinsons. The relationship betweem virulence of Xcc and the plasmid DNA restriction profile was not confirmed.

Vinte e um isolados de Xanthomonas campestris pv. citri (Xcc), provenientes de cinco municípios do RS, foram cultivados em meio de cultura CYE (casitone, 1; extrato de levedura, 0,35; glicerol, 2; ágar, 15 g/1), com zero, 16, 32, 40, 48 , 64 , 80 , 96 , 112 e 128x10-2 nM de CuS04. A concentração mínima inibitória (CMI) de CuS04 foi de 40x10-2 nM para todos os isolados. O clone pCuR2.A de X. campestris pv. vesicatoria, associado com resistência ao cobre, foi utilizado como sonda para detecção de homologia com o ADN total de Xcc. Não houve hibridização com o ADN total de nenhum dos 21 isolados. Quando o ADN plasmidial de 16 isolados foi digerido com as enzimas de restrição HindIII e BamHI, fragmentos, variando de 9 a 10 kb e 4 a 5 kb, respectivamente, foram detectados com maior frequência. Os plasmídeos apresentaram grande polimorfismo, porém a análise de grupos hierárquicos indicou a formação de pelo menos três grupos distintos. O uso de perfis de restrição para identificação de Xcc dependerá da escolha de perfis realmente representativos de cada grupo para viabilizar comparações. A relação entre a virulência de Xcc com o perfil de restrição plasmidial não foi confirmada. / Twenty one isolates of Xanthomonas campestris pv. citri (Xcc ), from five counties of RS, were grown on CYE (casitone, 1; yeast extract, 0. 35; glycerol, 2; agar 15 g per liter ) culture amended with zero, 16, 32, 40, 48, 64, 80, 96, 112 and 128x10-2 mM CuS04. The CuS04 minimum inhibitory concentration (CMI) was 40x10-2 mM to all isolates . The pCuR2.A clone of X. campestris pv. vesicatoria, associated with copper resistance, was used as a probe to detect homology with total DNA of Xcc. No hibridization with DNA of the 21 isolates was found. When hybridization with total DNA of 16 isolates was digested with Hind III and Bam HI restriction enzymes, fragments, ranging from 9 to 10 kb and 4 to 5 kb, respectively, were detected more frequently. There was great polymorphism among plasmids, and the a nalysis of hierarquical groups showed at least three distinct groups. The use of DNA restriction profile to ide ntify Xcc depends on a representative profile of each group to allow comparinsons. The relationship betweem virulence of Xcc and the plasmid DNA restriction profile was not confirmed.