Further mycological aspects of Ciborinia camelliae Kohn etiological agent of Camellia flower blight

Hara (1919) in Japan and Hansen & Thomas (1940) in California, in two different studies described a fungus named Sclerotinia camelliae which cause flower blight on Camellia japonica. In 1979 Kohn comparing the Japanese and new isolated strains, transferred this ascomycete into a new species named Ciborinia camelliae. In these researches, different morphocultural traits of the pathogen were described and some images and drawings of the fungal structures were published. Details of the infection process for C. camelliae are not well known since in the early 2000s when some studies were published regarding the first hours of pethal colonization. A century later its first description many aspects of the pathogen life are still unknown. One of the aims of our researches is to investigate deeply some mycological features of this pathogen. Eighty-two strains collected in Italy and abroad were analyzed. Therefore, a preliminary study was addressed to obtain a morphological description of the colonies and growth rates on four different media also considering the temperature influence from 5 to 30°C. Four different morphotypes have been described and one out of them resulted more frequent than the others. In addition, vegetative and reproductive structures were investigated in detail by light and scanning electron microscopy; hyphae, conidia, sclerotia, apotecia, asci, and ascospores were observed and a collection of more than 2000 photographs was obtained. The development of sclerotia from micelium and flowers was investigated in in vitro trials and the survival and germination of these structures, conidia and ascospores was also explored. In order to improve knowledge on potential control methods, the sensitivity of C. camelliae morphotypes to different fungicides was also assessed.