The objective of this study was to develop and validate a diagrammatic scale to evaluate the severity of spots on maize leaves caused by the fungus Diplodia macrospora. Severity ranged between the minimal (0.5%) and maximal (55%) limits of disease severity, and intermediate severity levels were defined according to the "Weber-Fechner stimulus response law". The proposed scale describes six levels of severity based on how much of the leaf is affected: 0.5%, 3%, 8%, 23%, 36%, and 55%. Validation was carried out by eight evaluators, four inexperienced and four experienced. They estimated the severity of disease in 60 maize leaves, with and without the proposed diagrammatic scale. A relationship was shown by regression analysis between estimated and actual severity, with and without the use of the scale. When both inexperienced and experienced evaluators used the scale, they were able to estimate disease severity more accurately and precisely.
A banana apresenta elevada suscetibilidade a doenças como as podridões que diminuem o tempo de prateleira do fruto. Uma das formas de controlar as doenças seria a utilização de métodos alternativos como os extratos de plantas medicinais. Assim, o objetivo deste estudo foi verificar a ação de formulados de alecrim (Rosmarinus officinalis L.) pó e líquido no controle de antracnose causada pelo fungo Colletotrichum musae (Berk & Curt.) Von Arx. e na maturação de banana ‘Nanicão’ em pós-colheita. Foram utilizadas as concentrações 0%; 0,25%; 0,5%; 1%; 1,5% e 2% do pó solúvel de extrato de alecrim diluído em água destilada, e as concentrações 0%; 0,5%; 1%; 2%; 4% e 6% do formulado aquoso contendo 21% de resíduo seco de alecrim diluído em água destilada. Foi realizada a mensuração da área de cada fruto e avaliada a severidade e a maturação a partir de porcentagem de área dos frutos, sendo os resultados utilizados para calcular a área abaixo da curva de progresso da doença (AACPD) e a porcentagem de maturação dos frutos. Realizou-se analise de regressão a partir dos dados obtidos e pode-se verificar que para o formulado de alecrim em pó a AACPD reduziu mais de 29% e para a maturação a redução foi de 21,72%. Para o formulado líquido a redução foi de 14,31% para AACPD e cerca de 10% para maturação. Assim, concluiu-se que houve eficiência por parte dos formulados de alecrim no controle da antracnose e no aumento da vida de prateleira da banana ‘Nanicão’.
This review article has aimed at environment and impact of different pollutants, define, classify, analyze and cite methods of remediation according to Brazilian environmental legislation. Concerns about the preservation of the environment is extensively debated nowadays, with a view mainly to the production of effluents in agriculture, toxic metals, emerging pollutants and excessive use of agrochemicals. However, some impacts are necessary to meet the needs of economic development and social to ensure they are carried out rationally. Furthermore, application of remediation methods reduce the impact of these pollutants as small as possible. In this sense, the environment's definition, the main current impacts, the size and consequences of these and some remediation methods, as well as Brazilian environmental legislation will be addressed.
O fungo Diplodia macrospora é agente causal de doenças na cultura do milho, sendo responsável por diminuição da produção. Entre inúmeras formas de controle de doenças pode-se citar a utilização de extratos vegetais. Diante disto, o objetivo deste estudo foi verificar a ação do extrato de guaco, orégano, arruda, gengibre, penicilina, pulmonária, alecrim, eucalipto, romã e osmarin, contra D. macrospora. O ensaio foi realizado em delineamento interiramente casualisado sendo utilizado para cada extrato as concentrações 0%, 1%, 2,5%, 5%, 7,5% e 10%. Os extratos foram obtidos pela trituração de parte do vegetal com água sendo o extrato bruto aquoso resultante utilizado na confecção dos meios de cultura. Realizou-se a avaliação do crescimento micelial a cada 24 horas, calculou-se a área abaixo da curva de progresso do crescimento micelial (AACCM) e realizada uma análise de regressão para cada extrato. Os extratos de guaco, orégano, arruda, gengibre, penicilina, pulmonária, alecrim, eucalipto, romã e osmarin, proporcionaram redução de aproximadamente 60, 85, 80, 55, 35, 42, 53, 89, 87 e 23% no crescimento micelial, sendo possível concluir que houve efeito positivo dos extratos contra o fungo D. macrospora.
The area cultivated with wheat has been increasing in the savannahs of the state of Minas Gerais, Brazil. Aphids are usually one of the main pests of wheat in many regions of the world; however, little is known about the aphid population in this new environment. The southern region of Brazil, the main wheat production area, has had several problems as a result of aphids, but aphid populations and the resulting impact on wheat production have not been investigated in these new crop production areas. Understanding control strategies to manage this insect could be essential for the “Cerrado” wheat that is grown in this area. The application of silicon (Si) has the potential to reduce the population growth of wheat aphids; however no field studies have been reported. Hence, we evaluated the effect of Si fertilization via soil application on the aphid populations and species composition and on yield components of wheat in three locations in Minas Gerais; the experiment was repeated simultaneously in Uberlândia, at the experimental areas of UFU and IFTM, and in Montes Claros, at the experimental area of UFMG, using the cultivars BRS 264 and BRS 394. The aphids first appeared just before wheat earing; they were then sampled six times over the course of the study, seven days apart, starting from 45 days after sowing. The aphid species Sitobion avenae (Fabricius), Schizaphis graminum (Rondani), and Rhopalosiphum padi (Linnaeus) were observed in all three locations; S. avenae was the dominant species in all locations. The experimental area of UFU had the highest number of S. avenae aphids per tiller for both cultivars, while UFMG had the lowest populations. Aphid populations and wheat yield components were not affected by soil Si fertilization. There was no difference in yield as a result of location or cultivar, but the location UFU and the cultivar BRS 394 had the greatest average hectoliter weight.
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