Chemical approaches to manage coffee leaf rust in drip irrigated trees

摘要

The purpose of this study was to assess the efficiency of chemical approaches to manage coffee leaf rust (CLR) in drip-irrigated coffee trees. Coffea arabica plants of the Catuai Vermelho IAC 144 cultivar were subjected to applications of protective and systemic fungicides from December 2000 to June 2006. The fungicide copper oxychloride was applied preventively in December, January, February and March. Foliar application of the systemic fungicide epoxiconazol was performed at predefined dates (calendar) and after ascertaining that CLR was present in 10% of plants. A fungicide + systemic insecticide (cyproconazol + thiamethoxam) was applied on the soil at the beginning of the rainy season. The results showed that a strategy based on two foliar application calendar for epoxiconazol at pre-determined times in December (0.6 L c.p.ha(-1)) and March (0.4 L c.p.ha(-1)) controlled CLR more effectively than four foliar application calendar for the protective fungicide copper oxychloride applied in December, January, February and March, at 3.0 kg c.p. ha(-1), application on the soil of fungicide + insecticide (cyproconazol + thiamethoxam) at the beginning of the rainy season and sampling and decision-making with foliar application of the systemic fungicide epoxiconazol at 0.6 L c.p.ha(-1) after ascertaining a 10% disease incidence. There was no significant difference in yield among the different strategies of fungicide applications across the six studied crops. The averages of coffee berry yield of all the treatments with fungicides either protective and or systemic were 30.80 (60-kg bags of processed coffee per hectare) which is 22.4% higher than the control treatment. In conclusion all the strategies can be used to control CLR including application of systemic fungicide after ascertaining a 10% disease incidence. The number of application of systemic fungicide epoxiconazol at 10% disease incidence was approximately 40% less than in a calendar system. This is the first report of the effective control of CLR with systemic fungicide epoxiconazol either spraying on the plants (performed at predefined dates or after ascertaining a 10% disease incidence) or through the application of cyproconazol on the soil in drip irrigation trees.