Health Status of Plane Trees (Platanus Spp.) In Spain
M.L. Tello, C. Redondo, and E. Mateo-Sagasta
Abstract: The plane tree (Platanus spp.) is one of the most frequently used ornamental trees in Spanish urban areas. For the past 30 years, the health of urban tree plantings in various parts of the Iberian Peninsula has been observed and a number of diseases, common to the majority of them, detected. The most frequently occurring diseases that affect Platanus spp. are anthracnose (caused by the fungi Sporonema platani Blauml.) and powdery mildew (caused by Microsphaera alni (DC.) Wint.), as well as diseases caused by other minor pathogens. Since 1997, we have focused our research on surveying the state of health of urban trees in the town of Aranjuez (Madrid), as an example of an urban location in central Spain. Within the numerous tree species that exist in the town, a serious problem was detected among plane trees. The symptoms observed (young shoots and branches up to 3 years old growing in whorls, necrotic tissue close to phloem and xylem, premature defoliation) indicate the possible existence of Gnomonia veneta (Sacc. et Speg.) Kleb, anamorph Sporonema platani Blauml. The majority of the trees show these symptoms to one degree or another. Applying diagnostic and identification methods in the laboratory, we were able to demonstrate the presence of 5. platani in all of the samples collected from symptomatic trees. A detailed description of the two main diseases, anthracnose and powdery mildew, in Spain is presented, with special reference to symptoms and dispersal under Spanish environmental conditions. A discussion about the most appropriate control methods is included.
Keywords: Sporonema platani; Microsphaera alni; Ceratocystis fimbriata; diseases; urban trees; anthracnose; powdery mildew; canker stain; phytopathological fungi.