Marigold Leaf Spot Caused by Alternaria tagetica New to Japan

In October 1998, a disease causing mainly foliar necrotic lesions was found on African marigold (Tagetes erecta) and French marigold (T. patula) grown in Miyagi Prefecture, Japan. Similar lesions also developed on stems and flowers, resulting in early blight of the affected organs. Plants with numerous lesions withered rapidly. A mitosporic fungus isolated repeatedly from the diseased plants was identified as Alternaria tagetica and demonstrated to cause the disease. The disease, as well as the fungus, is new to Japan. We propose the name “hanten-byô”, which means leaf spot in Japanese, for this disease.

Authors and Affiliations

1. Shikoku National Agricultural Experiment Station, Zentsuji 765–8508, Japan, , , , , , JP

   Keisuke TOMIOKA

2. National Institute of Agrobiological Resources, Tsukuba 305–8602, Japan, , , , , , JP

   Toyozo SATO

3. Chugoku National Agricultural Experiment Station, Fukuyama 721–8514, Japan, , , , , , JP

   Hiroki KOGANEZAWA

Received 5 April 2000/ Accepted in revised form 31 May 2000

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