5 research outputs found

    Avaliação da eficiência da mistura pronta de glyphosate + 2,4-D no controle da Commelina virginica L. em citros Efficacy evaluation of ready mixture of glyphosate + 2,4-D in Commelina virginica L. control in citrus

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    Um dos herbicidas mais utilizados para o controle de plantas daninhas em pós-emergência nos pomares cítricos paulistas é o glyphosate. No entanto, este herbicida aplicado isoladamente e nas doses recomendadas, tem proporcionado seleção da planta daninha trapoeraba (Commelina virginica L.), devido à grande tolerância da mesma, somada à eficiente eliminação das demais espécies da comunidade infestante. Em vista disso, e pela falta de opções , faz-se necessária a pesquisa de outros herbicidas ou misturas de herbicidas que sejam eficientes no controle da trapoeraba, de baixa toxicidade para os aplicadores, sistêmicos, e que sejam seletivos às plantas cítricas. O presente trabalho foi desenvolvido com o objetivo de estudar a eficiência da mistura pronta dos herbicidas glyphosate + 2,4-D amina no controle da trapoeraba em citros [Citrus sinensis (L.) Osbeck], em comparação com estes mesmos herbicidas aplicados isoladamente, bem como os possíveis efeitos fitotóxicos da mesma à cultura. O experimento foi instalado na região de Catanduva-SP, em um pomar de laranja Pera clone Rio, enxertada sobre limão Cravo, com dez anos de idade, plantado em um espaçamento de 8,0 x 6,5 m. A aplicação dos herbicidas foi realizada em 20 de fevereiro de 1991, de forma dirigida, em pós-emergência tardia da trapoeraba, quando a mesma já florescia e tinha altura variável entre 15 e 60 cm. A análise e interpretação dos resultados obtidos mostraram que a mistura pronta de glyphosate + 2,4-D apresenta um controle superior da trapoeraba em relação aos produtos aplicados isoladamente, não havendo diferenças significativas no controle para doses superiores a 0,60 + 0,80 kg i.a./ha. Os dados obtidos reforçam a teoria de sinergismo entre os dois produtos. Em nenhum dos tratamentos foi verificado sintomas visuais de intoxicação nas laranjeiras.<br>In citrus orchard of São Paulo state, Brazil, one of the most employed post-emergency herbicide for weed control is glyphosate. However, when this herbicide is applied alone and at the recommended rates, it has been observed a selection of the weed Commelina virginica L. due to its great tolerance and the elimination of other weeds. Because of that, other chemicals must be studied to solve the problem. In this particular case, the herbicide should be sistemic and have a low toxicity to the operator and to the citrus trees. This work was conducted to study the efficacy of a ready mixture of glyphosate + 2,4-D compared to the products sprayed alone in orange orchards [Citrus sinensis (L.) Osbeck]. The phytotoxicity effects were studied too. The experiment was carried out in Catanduva, São Paulo, Brazil, in a ten years old orange orchard, with 8,0 x 6,0m spacing. On february, 20 th, 1991, the herbicides were sprayed directly on 15-60cm height Commelina during its flowering. The results showed that the ready mixture was better in Commelina control than other treatments. No significant differences were observed for the rates greater than 0,60 + 0,80 kg a.i./ha. The results reinforced the sinergism theory within both products. None of the treatments caused visual phytotoxicity to orange trees

    A second update on mapping the human genetic architecture of COVID-19

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    Mapping the human genetic architecture of COVID-19

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    The genetic make-up of an individual contributes to the susceptibility and response to viral infection. Although environmental, clinical and social factors have a role in the chance of exposure to SARS-CoV-2 and the severity of COVID-191,2, host genetics may also be important. Identifying host-specific genetic factors may reveal biological mechanisms of therapeutic relevance and clarify causal relationships of modifiable environmental risk factors for SARS-CoV-2 infection and outcomes. We formed a global network of researchers to investigate the role of human genetics in SARS-CoV-2 infection and COVID-19 severity. Here we describe the results of three genome-wide association meta-analyses that consist of up to 49,562 patients with COVID-19 from 46 studies across 19 countries. We report 13 genome-wide significant loci that are associated with SARS-CoV-2 infection or severe manifestations of COVID-19. Several of these loci correspond to previously documented associations to lung or autoimmune and inflammatory diseases3,4,5,6,7. They also represent potentially actionable mechanisms in response to infection. Mendelian randomization analyses support a causal role for smoking and body-mass index for severe COVID-19 although not for type II diabetes. The identification of novel host genetic factors associated with COVID-19 was made possible by the community of human genetics researchers coming together to prioritize the sharing of data, results, resources and analytical frameworks. This working model of international collaboration underscores what is possible for future genetic discoveries in emerging pandemics, or indeed for any complex human disease
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