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

DETECTION METHODS, TRANSMISSION AND PATHOGENICITY OF Fusarium spp IN Pinus taeda SEEDS

A podrid\ue3o-de-raiz (PR), causada por Fusarium spp., ocasiona perdas de pl\ue2ntulas no viveiro que apresentam, inicialmente, descolora\ue7\ue3o das ac\uedculas para tom verde-amarelado seguida de curvatura apical, murcha e consequente morte da muda. Os objetivos deste trabalho foram: a) determinar o m\ue9todo adequado e eficiente para detec\ue7\ue3o de Fusarium spp. nas sementes de Pinus taeda; b) verificar se h\ue1 transmiss\ue3o de Fusarium spp. das sementes para as pl\ue2ntulas de Pinus taeda; c) desenvolver uma escala descritiva para avaliar a severidade da PR em mudas de Pinus taeda; d) avaliar a patogenicidade, agressividade e \ue1rea abaixo da curva de progresso da doen\ue7a (AACPD) de isolados de Fusarium spp. Para detec\ue7\ue3o foram aplicados tr\ueas tratamentos em seis lotes de sementes de Pinus taeda, sendo quatro repeti\ue7\uf5es de 25 sementes: blotter test, papel-cart\ue3o e meio seletivo. A transmiss\ue3o foi avaliada em sementes de seis lotes de Pinus taeda durante 60 dias contabilizando-se a percentagem de pl\ue2ntulas emergidas (PE), sementes n\ue3o germinadas (SNG) e de SNG com Fusarium spp. Uma escala descritiva de notas foi desenvolvida para avaliar a severidade de PR em mudas de Pinus taeda. A severidade e a incid\ueancia da doen\ue7a foram avaliadas aos 7, 14, 21 e 28 dias ap\uf3s a inocula\ue7\ue3o das mudas de Pinus taeda de seis meses de idade. Foi avaliada a patogenicidade, a severidade e a incid\ueancia de doze isolados de Fusarium spp. obtidos no teste de detec\ue7\ue3o Para o teste de patogenicidade e agressividade foram 13 tratamentos com 15 repeti\ue7\uf5es. O m\ue9todo de detec\ue7\ue3o mais sens\uedvel ao detectar Fusarium spp. em sementes de Pinus taeda foi o meio seletivo. N\ue3o foi observada transmiss\ue3o de Fusarium spp. das sementes para as pl\ue2ntulas, no entanto, Fusarium spp. causou apodrecimento de sementes na fase de germina\ue7\ue3o; a escala descritiva permitiu a avalia\ue7\ue3o da progress\ue3o dos sintomas da doen\ue7a PR; nove isolados de Fusarium spp. mostraram-se patog\ueanicos a mudas de Pinus taeda, reproduzindo sintomas t\uedpicos da PR, sendo o isolado L3R2 o mais agressivo e o que exibiu maior AACPD.The root rots (RR), caused by the Fusarium spp., causes loss of seedling in the nursery that show, initially, discoloration of the needles to a yellowish-green tone followed by apical curvature, wilt and the consequent death of the seedling. The objectives of this work were to: a) define the most appropriate and efficient method to detect Fusarium spp. in Pinus taeda seeds; b) verify if there is transmission of Fusarium spp. from seeds to Pinus taeda seedlings; c) develop a descriptive scale to evaluate the severity of the RR in Pinus taeda seedlings; d) evaluate the pathogenicity, aggressiveness and area under the disease progress curve (AUDPC) of isolated Fusarium subglutinans. For detection three treatments were applied to six lots of Pinus taeda seeds, bein four repetitions of 25 seeds: blotter test, paper card and selective medium. The transmission was evaluated in seeds from six lots of Pinus taeda during 60 days counting the percentage of emerged plantlet (EP), non-germinated seeds (NGS) and from NGS seeds with Fusarium spp. A descriptive scale of grades was developed to evaluate the severity of RR in Pinus taeda seedlings. The severity and the incidence of the illness were evaluated at 7, 14, 21 and 28 days after the inoculation from Pinus taeda seedlings of six months of age. The pathogenicity, severity and incidence of twelve isolated Fusarium subglutinans obtained in the detection test. To test for pathogenicity and aggressiveness 13 treatments with 15 replications were applied. The most sensitive detection method to detect Fusarium spp. on Pinus taeda seeds was the selective medium; transmission was not observed of Fusarium spp. from seeds to the seedlings; the descriptive scale allowed evaluating the progression of RR symptoms; nine isolated of Fusarium spp. were found to be pathogenic to Pinus taeda seedlings, reproducing typical symptoms of RR, being isolated L3R2, the most aggressive and that exhibited higher AUDPC