Pathogenicity of fungi isolated from Quercus suber in Catalonia (NE Spain)

Thirty-four fungal species isolated from cork oak (Quercus suber) in Catalo nia (NE Spain) during 1992-95 were tested for pathogenicity either in stem, leaf or root inoculations. Eleven species were found to be pathogenic on s tem: Biscogniauxia mediterranea, Botryosphaeria stevensii, Diatrype ci. sti gma, Endothia gyrosa, Fusarium solani, Graphium sp., Ophiostoma quercus, Ph omopsis sp., Phytophthora cinnamomi, Sporendocladia bactrospora and an unid entified Coelomycete. Three fungi showed pathogenic effects on leaves: Dend rophoma myriadea, Lembosia quercina and Phomopsis quercella. No clear patho genic effects were detected in the root inoculation experiment. Trunk patho gens were differentiated into two groups according to the effects induced i n the inoculated plants; B. stevensii, Phomopsis sp. and P. cinnamomi cause d the death of the inoculated plants and induced the formation of large can kers and vascular necroses. The other pathogenic species also produced seve re 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 fung i. However, water stress did not significantly affect the damage caused by B. stevensii, which was the most virulent of the species tested. Leaf patho gens only showed their effects if the leaf cuticle was previously damaged. Lembosia quercina caused small dark lesions whereas D. myriadea and P. quer cella produced large necrotic areas in well-watered plants. The lesions cau sed by the last two fungi were reduced by water stress.