IMPACT OF Cylindrocladium candelabrum LEAF SPOT IN YOUNG PLANTATIONS OF Eucalyptus benthamii IN RIO NEGRINHO, SANTA CATARINA STATE

Eucalyptus benthamii \ue9 uma das esp\ue9cies florestais plantada na regi\ue3o Sul do Brasil devido \ue0 sua resist\ueancia \ue0 geada. A principal doen\ue7a em plantios comerciais \ue9 a mancha foliar causada por Cylindrocladium candelabrum . O objetivo deste trabalho foi avaliar a incid\ueancia e a severidade da doen\ue7a em plantios de Eucalyptus benthamii, localizados em Rio Negrinho - SC. O levantamento foi realizado em tr\ueas plantios (quatro, oito e 18 meses de idade), quantificando-se a incid\ueancia pelo percentual de plantas doentes e a severidade com uma escala diagram\ue1tica que variou de 0 (sem mancha e desfolha) a 5 (mais de 75 % de desfolha). Quatro avalia\ue7\uf5es foram feitas no per\uedodo de julho/2011 a junho/2013. A incid\ueancia m\ue9dia de \ue1rvores com a mancha foliar variou de 2,6 at\ue9 43,8 % das \ue1rvores, dependendo da idade, enquanto que a severidade m\ue9dia variou de 1,2 a 2,9, com menor severidade nas \ue1rvores de quatro e oito meses de idade. Verificaram-se rela\ue7\uf5es diretas entre a intensidade da doen\ue7a e o volume de precipita\ue7\ue3o pluviom\ue9trica, bem como entre severidade e altura da \ue1rvore. A rela\ue7\ue3o entre incid\ueancia de plantas com mancha foliar variou de acordo com a altura das \ue1rvores.Eucalyptus benthamii is one of the planted forest species in Southern Brazil due to its frost resistance. The main disease in commercial plantations is the leaf spot caused by Cylindrocladium candelabrum . The objective of this work was to evaluate incidence and severity of this disease in Eucalyptus benthamii plantations, in Rio Negrinho, SC state. The survey was performed in three plantations (4, 8 and 18 monthsold), quantifying the number of diseased trees and evaluating the severity by using a diagrammatic scale varying from 0 (no spot and shedding of leaves) to 5 (more than 75 % of defoliation). Four evaluations were done from July/2011 to June/2013. The average incidence of leaf spot on trees varied from 2.6 to 43.8 %, depending upon the age, while the average severity varied from 1.2 to 2.8, with low severity in trees of 4 and 8 months-old. It was verified increase on disease severity increasing tree age and the direct relationship between disease intensity and precipitation volume as well as between severity and tree height. The relationship between the incidence of plants with leaf spot varied according to tree heights