Chemical Control of Mycosphaerella Leaf Disease on Eucalyptus dunnii in Southern Brazil

Abstract

Mycosphaerella leaf disease (MLD) is a dangerous disease for eucalypt plantations; however little information is available regarding its control using fungicides in South America. In this study, we evaluated MLD control, and growth in young stands of Eucalyptus dunnii clones (C18 and C25). After two applications of azoxystrobin + cyproconazole (0.3 L/ha-1 and 0.45 L/ha-1), with a spraying volume of 200 L/ha-1 , and trifloxystrobin + tebuconazole (0.5 L/ha-1 and 0.75 L/ha-1), with a spraying volume of 100 L/ha-1 , mean severity reduction for apical branches of C18 was 74%. For middle branches, application of trifloxystrobin + tebuconazole at 0.5 L/ha-1 reduced severity by 27% in C18. While fungicide applications did not affect growth in height or root collar diameter, our results suggest that the application of fungicide can deter disease progression throughout the plant. Therefore, the monitoring of disease outbreaks is crucial to enable effective, early application.