Leônidas Leoni Belan

Nutrients distribution in diseased coffee leaf tissue

Knowing the structure and distribution of nutrients in plant tissues can clarify some mechanisms of pathogen attack in plants and plant defense against infection, thus helping management strategies. The aim of this study was verify differences in distribution of mineral nutrients in coffee leaf tissues around foliar lesions of bacterial blight of coffee, blister spot, cercospora leaf, phoma leaf spot and coffee leaf rust. Fragments of leaf tissue surrounding the lesions were dehydrated in silica gel, carbon covered and subjected to X-ray microanalysis (MAX). Thirty-three chemical elements were detected in leaf tissue; however, there was variation in potassium and calcium contents surrounding the lesions. The highest potassium content was found in asymptomatic tissues surrounding the lesions, decreasing toward the transition zone and reaching minimum content in symptomatic tissues. The highest calcium content was found in symptomatic tissues, decreasing toward the transition zone and reaching minimum content in asymptomatic tissues. Therefore, MAX can be used to analyze the composition and distribution of nutrients in plant tissues and, if associated with mineral nutrition, it may help understand host-pathogen relationships and plant disease management.

Análise geoestatística do “vira-cabeça” na cultura do tomateiro

IFES Instituto Federal de Educacao Ciencia e Tecnologia do Espirito Santo - Campus Montanha

Controle da antracnose e da mancha angular do feijoeiro comum com indutores de resistência

Avaliou-se a influencia de indutores de resistencia no controle de doencas do feijoeiro. Avaliou duas doses de silicato de calcio combinadas com silicato de potassio, acibenzolar-S-metil (ASM), ortofosfato, fosfito de manganes, sulfato de manganes, fungicida e agua, sobre a severidade, incidencia da antracnose e desenvolvimento dos feijoeiros. O segundo experimento avaliou o efeito de seis tratamentos foliares (cinco indutores de resistencia e agua) com e sem fungicidas sobre o controle de antracnose, mancha angular e rendimento. Moleculas indutoras de resistencia influenciaram a incidencia e a severidade da antracnose. Plantas tratadas com ASM, ortofosfato, sulfato de manganes e fosfito de manganes apresentaram reducao de 10,3% na area abaixo da curva de progressao da severidade, em relacao a testemunha. Nao houve efeito da suplementacao de silicato de calcio sobre o controle da antracnose e desenvolvimento das plantas. Plantas pulverizadas com ortofosfato e extrato de casca de cafe apresentaram valores de area abaixo da curva de progressao da incidencia da antracnose menores que a testemunha. Nao houve influencia dos indutores de resistencia sobre a severidade da antracnose e a mancha angular. O uso de indutores, quando combinado a fungicidas, nao proporcionou efeito adicional no controle de doencas e na produtividade do feijoeiro.