INFLUÊNCIA DA MANCHA FOLIAR DE MYCOSPHAERELLA NO DESENVOLVIMENTO DE Eucalyptus dunnii NA REGIÃO SERRANA DE SANTA CATARINA

Abstract

Aiming to deduce the influence of the leaf disease caused by species of Mycosphaerella and Teratosphaeria on growth of Eucalyptus dunnii plantations was analyzed the stand growth responses of two attacked clones at two different age ranges in south of Brazil in the areas of Klabin S. A. Growth responses expressed by height, diameter and stem base biomass and disease severity were evaluated during the months of April, June, September and November 2014 in areas that had typical leaf spots of Mycosphaerella and Teratosphaeria. A total of 2232 plants altogether were evaluated for the plant growth in function of disease severity, the growth and severity in function of levels of defoliation of 25%, 50% e 75% of the total crown height at the beginning of the experiment and the fungicides applications of Trifloxystrobin and Tebuconazole in a spray volume of 200 L/ha with 0,5 L/ha and 0,75 L/ha of the commercial product and Azoxystrobin and Cyproconazole in a spray volume of 100 L/ha with 0,3 L/ha and 0,45 of the commercial product. From the foliar assays collected in the field it wasn`t able to obtain isolates to confirm the pathogens associated with the leaf spots in the Eucalyptus dunnii stands. Clones with higher disease severity and defoliation with a attack pattern from base to the top of the crown, specially to the young trees, had lower growth of height, diameter and stem base biomass. The defoliation lead to an increase of the disease severity and influenced the diameter growth of the trees, to the leaf spot control in the plantations the fungicides application weren`t effective to control the disease.