Coffee Science
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3355
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Resultados da Pesquisa
Item Infection process of Cercospora coffeicola in immature coffee fruits(Editora UFLA, 2019-01) Paula, Paulo Victor Augusto Azevedo de; Pozza, Edson Ampélio; Alves, Eduardo; Moreira, Silvino Intra; Paula, Júlio Cesar Azevedo; Santos, Leandro AlvarengaCercosporiosis is caused by Cercospora coffeicola and represents a very important coffee plants phytosanitary problem. Catuaí IAC 144 and Topázio cultivars at the F2 stage were inoculated with a conidial suspension. Samples were collected at 4, 8, 12, 24, 36, 48, 72, 96, and 168 hours after inoculation (hai) for scanning electron microscope studies. Fungal germination in epidermal surface occurred four hai; penetration only through epidermal wounds, without appressoria, started at 12 hai while the mycelial colonization occurred at 72 hai. The infection in immature coffee fruits implies brown eyespot control management anticipation need, even before the first symptoms.Item Phytotoxicity of mineral, vegetable oils and foliar fertilizers in coffee seedlings(Editora UFLA, 2017-01) Santos, Leandro Alvarenga; Pozza, Edson Ampélio; Souza, Paulo Estevão deThe objective of this study was to evaluate the toxicity in coffee seedlings caused by mineral oil, vegetable and foliar fertilizer, applied in different radiation intensities. In the first experiment not observed symptoms of phytotoxicity in the control plants and sprayed with foliar fertilizer. Two experiments to study the phytotoxic action of oils and foliar fertilizers were performed. The first was evaluated phytotoxic effects of mineral oil, vegetable oil and foliar fertilizer in different application times. In the second experiment evaluated the intensity of radiation in the occurrence of toxicity symptoms caused by both oils. At the end of the second experiment samples were taken to perform scanning electron microscopy. Plants sprayed 12:00 h had higher incidence and severity of injuries to both oils in relation to others (9:00 and 17:00h). In the light intensity experiment proved that the increase of light intensity from 80 to 320 μmol/m2/s promoted an increase in symptoms of phytotoxicity. In the analysis of lesions by scanning electron microscopy, deformations on the leaf surface caused by mineral oil and also for vegetable oil were observed.Item Effect of temperature and leaf wetness on Phoma tarda and phoma leaf spot in coffee seedlings(Editora UFLA, 2015-01) Lorenzetti, Emi Rainildes; Pozza, Edson Ampélio; Souza, Paulo Estevão de; Santos, Leandro Alvarenga; Alves, Eduardo; Silva, André Costa da; Maia, Fernanda Gonçalves Martins; Carvalho, Rejane Rodrigues da CostaPhoma leaf spot is a major disease of coffee plants in regions with specific conditions of temperature and humidity. Despite the importance of environmental variables for disease progression, so far they have been poorly understood. Thus, we assessed the effect of different temperatures (15, 20, 25 and 30 oC) on mycelial growth, production and germination of conidia of Phoma tarda; and the same effect of temperature (15, 20, 25 and 30 oC) and leaf wetness duration (6, 12, 24, 36 and 48 hours) on fungal infection and severity of disease over time in coffee plants. Disease assessment was integrated in the area using the disease progress curve (AUDPC) and the infection processes were observed by scanning electron microscopy (SEM). The optimal temperatures for fungus growth, conidial production and germination in vitro were 22.9, 29.8, and 25.1 °C, respectively. Temperatures ranging from 15-20 °C significantly increased germ tube length and provided favorable conditions for pathogen infection through observation of early events such as cuticle separation from leaf tissue. The same temperature range combined with increasing leaf wetness periods, reached the highest value of the AUDPC of phoma leaf spot. Thus, it was found that both temperature and leaf wetness duration in the variables assessed and the difference in relation to temperature for in vitro growth and sporulation for in vivo tests were important.Item Nova técnica para isolar Cercospora coffeicola Berkeley & Cooke, agente etiológico da cercosporiose do cafeeiro(Editora UFLA, 2014-01) Santos, Leandro Alvarenga; Souza, Paulo Estevão de; Pozza, Edson Ampélio; Caldeira, Douglas Massimo; Botelho, Deila Magna dos SantosA mancha do olho pardo é uma doença endêmica no Brasil. Poucos são os trabalhos publicados sobre essa doença devido à dificuldade de isolamento e de produção de inóculo do fungo Cercospora coffeicola. Objetivou-se, neste trabalho, divulgar a técnica de isolamento desenvolvida e utilizada na Universidade Federal de Lavras, denominada Técnica da Pipeta. Através dela mais de 70 isolados já foram obtidos para estudos futuros do agente etiológico dessa importante doença.