Efeito de fungicidas e influência de fatores climáticos sobre a mancha manteigosa no cafeeiro / Effect of fungicides and influence of climatic factors on the blister spot of coffee trees

RESUMO

Neste trabalho, objetivou-se avaliar a eficiência de alguns fungicidas no controle da mancha manteigosa (Colletotrichum gloeosporioides) do cafeeiro (Coffea arabica L.) em campo, e verificar os efeitos climáticos no progresso da doença. Foram conduzidos ensaios sobre cafeeiros da cultivar Catucaí Vermelho, com aproximadamente 8 anos de idade. Os fungicidas testados foram tetraconazol, triadimenol, chlorotalonil e mancozeb, nas dosagens de 1,0L/ha, 12Kg/ha, 3Kg/ha e 2Kg/ha, respectivamente. Coletaram-se dados climáticos diariamente, no período de outubro de 2004 a maio de 2006. Os fungicidas chlorotalonil e triadimenol foram os que proporcionaram os melhores resultados de eficiência de controle do progresso de morte de ramos e frutos, destacando a produção de frutos cereja. Entre os meses de outubro a janeiro, verificou-se elevado progresso de mortes de ramos influenciado pelas altas precipitações pluviais. Os fungicidas tetraconazol e o mancozeb mostraram-se ineficientes. Plantas com mancha manteigosa, mesmo quando pulverizadas com fungicidas, tiveram significativa queda de frutos, enquanto plantas sadias apresentaram produções 95% superiores àquelas.

ABSTRACT

The aim of this work was to assess the effect of selected fungicides on the control of coffee blister spot in the field and to verify the climatic effects on the progress of the disease. Trials were carried out with coffee plants of cultivar Catucaí Vermelho, approximately 8 years old. The fungicides tested were tetraconazol (1L/ha), triadimenol (12Kg/ha), chlorothalonil (3Kg/ha), and mancozeb (2Kg/ha). Climatic data were collected daily from October 2004 to May 2006. The fungicides chlorotalonil and triadimenol provided the best efficiency results on the control of the progress of die-back and the number of fruits, with an increase in the cherry production. The increase of die-back during the period from October to January was possibly induced by the rainfall. Tetraconazol and mancozeb were not efficient. Coffee trees affected by blister spot, even if treated with fungicides, had significant decrease in the fruit production and the untreated healthy trees had their yield 95% higher than of those treated.