A new disease of chrysanthemum causing ray speck was found in Okinoerabu island, Kagoshima, Japan in March 2006. Small reddish-brown lesions were observed on the ray florets of the chrysanthemum (cv. Anastasia). The causal fungus was exclusively isolated from the lesions, and typical symptoms were reproduced after inoculation with the isolate. The causal fungus was identified as Stemphylium lycopersici (Enjoji) Yamamoto based on morphology and the sequences of rDNA-ITS and the gpd gene regions. The name, ''sho-hanten-byo'', in Japanese is proposed for this ray speck disease.Keywords Chrysanthemum Á New disease Á Ray speck Á Stemphylium lycopersici Chrysanthemums (Chrysanthemum morifolium Ramat. Dendranthema grandiflorum Kitam.) are the most economically valuable cut flower in Japan. Although chrysanthemums are generally harvested when the blossoms are about one-third open, some cultivars such as cv. Anastasia that are characterized by their large ray florets and popular for flower arrangements are cut when fully open, small reddish-brown lesions were observed on ray florets of these cultivars used for flower arrangements, and the disease was diagnosed as ray speck. The causal fungus was identified as Stemphylium lycopersici (Enjoji) Yamamoto. This is the first report of chrysanthemum ray speck caused by S. lycopersici in Japan. Occurrence and symptomsIn March 2006, small reddish-brown lesions were observed on ray florets of the chrysanthemum (cv. Anastasia) in a carvel-built house on Okinoerabu island, Kagoshima Prefecture, Japan. Reddish-to purplish-brown, round lesions about 0.1 mm in diameter were first observed on the ray florets. Later, the lesions enlarged and covered half of the ray florets (Fig. 1a). In June 2006, leaf necrosis was also observed on cv. Kiruke in the same locality. No signs of the causal fungus were observed on the ray florets or the leaves. The symptoms on the ray floret are quite similar to ray speck of chrysanthemums reported in the USA (Tammen 1963). Isolation and morphology of the fungusThe diseased tissues form the ray floret (cv. Anastasia) and the leaf (cv. Kiruke) were excised, surface-sterilized for 2- N. Nishi (&)

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