A New Disease for Europe of Ficus microcarpa Caused by Botryosphaeriaceae Species

Abstract

The Indian laurel-leaf fig (Ficus microcarpa) is an important ornamental tree widely distributed in the urban areas of Italy. Surveys conducted in 2019 and 2020 on several tree-lined streets, squares, and public parks in Catania and Siracusa provinces (Sicily, southern Italy) revealed the presence of a new disease on mature trees. About 9% of approximately 450 mature plants showed extensive branch cankers and dieback. Isolations from woody tissues obtained from ten symptomatic plants consistently yielded species belonging to the Botryosphaeriaceae family. The identification of the recovered fungal isolates was based on a multi-loci phylogenetic (maximum parsimony and maximum likelihood) approach of the ITS, tef1-α, and tub2 gene regions. The results of the analyses confirmed the presence of three species: Botryosphaeria dothidea, Neofusicoccum mediterraneum, and N. parvum. Pathogenicity tests were conducted on potted, healthy, 4-year-old trees using the mycelial plug technique. The inoculation experiments revealed that all the Botryosphaeriaceae species identified in this study were pathogenic to this host. Previous studies conducted in California showed similar disease caused by Botryosphaeriaceae spp., and the pathogenic role of these fungi was demonstrated. To our knowledge, this is the first report of Botryosphaeriaceae affecting Ficus microcarpa in Europe.

Identification and Characterization of Neofusicoccum stellenboschiana in Branch and Twig Dieback-Affected Olive Trees in Italy and Comparative Pathogenicity with N. mediterraneum

“…In the context of the BTD of olive trees in Apulia [ 22 ], N. stellenboschiana arises in this work as an additional botryosphaeriaceous agent of this syndrome in line with the fact that Botryosphaeriaceae typically co-infect the host leading to disease expression. “Botryosphaeria dieback” of grapevine is the most studied of this taxonomically-related-multi-agent type of disease [ 23 ], but several other examples can be cited in which shoot wilting, dieback, branch canker, wood discolouration, and the death of trees are strictly linked to the colonization of diverse pathogenic Botryosphaericeae species, especially those in the genus Neofusicoccum , Diplodia and Lasiodiplodia : decline and mortality of Eucaliptus camaldulensis in Sardinia (Italy) [ 43 ], dieback and cankers of Loquat [ 44 ], decline of almond [ 45 ], dieback of lentisk [ 46 ], canker and dieback of oleaster [ 18 ], branch and twig dieback of olive trees in Spain and California (USA) [ 11 , 13 ], branch cankers and dieback of Citrus and Ficus microcarpa trees [ 47 , 48 ].…”