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Summary Botryosphaeria canker of cork oak (Quercus suber L.), caused by Botryosphaeria corticola, is a well-known factor contributing to the decline of this forest species and is a serious disease in the main cork-producing countries of the Western Mediterranean basin. In this work, fungicides with the potential for controlling the disease were selected using a combination of in vitro tests and field trials. Fourteen fungicides in different chemical families were tested in vitro to evaluate their effect on inhibition of mycelial growth. The most effective fungicides were benomyl, carbendazim, cyprodinil + fludioxonil, thiabendazol and thiophanate-methyl; these compounds were then further tested under field conditions. In the field trials, carbendazim and thiophanate-methyl were the most effective fungicides, as shown by efficacy indices, in reducing debarked trunk surface affected by cankers (76% and 50–65%, respectively). These results suggest that the occurrence of Botryosphaeria canker on cork oak can be reduced effectively with the application of selected fungicides after cork removal from the trees.

Summary Thirty-four fungal species isolated from cork oak (Quercus suber) in Catalonia (NE Spain) during 1992–95 were tested for pathogenicity either in stem, leaf or root inoculations. Eleven species were found to be pathogenic on stem: Biscogniauxia mediterranea, Botryosphaeria stevensii, Diatrype cf. stigma, Endothia gyrosa, Fusarium solani, Graphium sp., Ophiostoma quercus, Phomopsis sp., Phytophthora cinnamomi, Sporendocladia bactrospora and an unidentified Coelomycete. Three fungi showed pathogenic effects on leaves: Dendrophoma myriadea, Lembosia quercina and Phomopsis quercella. No clear pathogenic effects were detected in the root inoculation experiment. Trunk pathogens were differentiated into two groups according to the effects induced in the inoculated plants; B. stevensii, Phomopsis sp. and P. cinnamomi caused the death of the inoculated plants and induced the formation of large cankers and vascular necroses. The other pathogenic species also produced severe cankers and vascular lesions, but no significant mortality was detected. Water stress increased the lesions caused by B. mediterranea and Phomopsis sp., but limited those of P. cinnamomi and the rest of the inoculated fungi. However, water stress did not significantly affect the damage caused by B. stevensii, which was the most virulent of the species tested. Leaf pathogens only showed their effects if the leaf cuticle was previously damaged. Lembosia quercina caused small dark lesions whereas D. myriadea and P. quercella produced large necrotic areas in well-watered plants. The lesions caused by the last two fungi were reduced by water stress. Resume Le pouvoir pathogene de trente-quatre especes fongiques isolees de chene liege en Catalogne (nord-est de l’Espagne) de 1992 a 1995 a ete teste par inoculation sur tronc, feuilles et racines. Onze especes se sont montrees pathogenes sur tronc: Biscogniauxia mediterranea, Botryosphaeria stevensii, Diatrype cf. stigma, Endothia gyrosa, Fusarium solani, Graphium sp., Ophiostoma quercus, Phomopsis sp., Phytophthora cinnamomi, Sporendocladia bactrospora et un Coelomycete non identifie. Trois champignons ont eu un effet pathogene sur feuilles: Dendrophoma myriadae, Lembosia quercina et Phomopsis quercella. Aucun effet clair n’a ete detecte chez les inoculations de racines. Les pathogenes de tronc se repartissaient en deux groupes selon leurs effets en inoculation; B. stevensii, Phomopsis sp. et P. cinnamomi provoquaient la mort des plants et induisaient le formation de grands chancres et des necroses vasculaires. Les autres especes pathogenes produisaient aussi des chancres graves et des lesions vasculaires, mais pas de mortalite significative. Un stress hydrique augmentait les lesions provoquees par B. mediterranea et Phomopsis sp. mais limitait ceux de P. cinnamomi et des autres champignons inocules. Cependant, le stress hydrique n’affectait pas significativement les degâts par B. stevensii qui etait la plus agressive des especes testees. Les pathogenes foliaires n’avaient d’effet que si la cuticule foliaire etait prealablement endommagee. Lembosia quercina provoquait de petites lesions sombres et D. myriadea et P. quercella provoquaient de grandes plages necrotiques chez les plants bien arroses; les lesions causees par ces deux derniers champignons etaient reduites par le stress hydrique. Zusammenfassung Die Pathogenitat von 34 Pilzarten, die im Zeitraum 1992–1995 von Korkeichen (Quercus suber) in Katalonien (NO-Spanien) isoliert wurden, wurden mit Hilfe von Trieb-, Blatt- oder Wurzelinokulationen untersucht. Am Stamm erwiesen sich 11 Arten als pathogen: Biscogniauxia mediterranea, Botryosphaeria stevensii, Diatrype cf. stigma, Endothia gyrosa, Fusarium solani, Graphium sp., Ophiostoma quercus, Phomopsis sp., Phytophthora cinnamomi, Sporendocladia bactrospora und ein nicht identifizierter Coelomycet. Drei Arten verursachten Symptome auf Bla¨ttern: Dendrophoma myriadea, Lembosia quercina und Phomopsis quercella. Bei den Wurzelinokulationen wurden keine pathogenen Effekte beobachtet. Bei den Stammpathogenen wurden nach den von ihnen an den inokulierten Pflanzen verursachten Symptomen zwei Gruppen unterschieden: B. stevensii, Phomopsis sp. und P. cinnamomi verursachten den Tod der Pflanzen und induzierten die Bildung von grossen Rinden- und Xylemnekrosen. Die anderen pathogenen Arten verursachten ebenfalls starke Rindennekrosen und Gefa¨ssla¨sionen, es wurde jedoch keine auffallende Mortalita¨t beobachtet. Unter Wasserstress war die durch B. mediterranea und Phomopsis sp. induzierte Nekrosebildung versta¨rkt, dagegen war sie bei P. cinnamomi und den u¨brigen inokulierten Pilzen reduziert. Wasserstress beeinflusst jedoch das Ausmass der Scha¨digung durch B. stevensii, der virulentesten der untersuchten Arten, nicht. Die Blattpathogene verursachten nur dann Symptome, wenn zuvor die Blattcuticula bescha¨digt worden war. Lembosia quercina verursachte kleine dunkle La¨sionen, wa¨hrend D. myriadea und P. quercella bei gut bewa¨sserten Pflanzen grosse Nekrosen verursachten. Diese Symptome waren unter Wasserstress weniger stark ausgepra¨gt.

Botryosphaeria stevensii Shoemaker (anamorph: Diplodia mutila Fr. apud Mont.) is reported as the cause of canker and dieback of cork oak (Quercus suber L.) in Catalonia (NE Spain). It also causes wilting of trees after cork is removed for industrial purposes. Symptomatology and details of morphology for both anamorph and teleomorph are given.