Sclerophthora macrospora (Japanese Fungi on Plants)

Japanese Fungi on Plants No.59 before next top

Sclerophthora macrospora (Sacc.) Thirum., Shaw & Naras. [Sclerospora oryzae Brizi]
Classification: Oomycota, Oomycetes, Peronosporales, Peronosporaceae

Widely distributed in Japan. Parasitizes many gramineous weeds such as wheatgrass, knotgrass, rescuegrass, green foxtail in addition to gramineous crops, causing crazy top or downey mildew. Oospores are produced in the leaf tissues and sporangia on the surface of leaves. Disperses by zoospores in free water of soil. Never grows on aritificial media.

Characteristics: Plant pathogen Symptom: JPEG (Sorghum, Crazy top, 34kb)

			Morphology: Teleomorph: Oogonia globose to subglobose, wall thickened, hyaline, 20-48 x 10-29 um, producing oospore filling oogonia. Antheridia hyaline, kidney-shaped, paragynous. Oospores germinate directly to produce zoosporangia. Anamorph: Zoosporangia ellipsoid to obovoid, hyaline, apical papillate, 60-114 x 28-50 um, germinating in water to release kidney-shaped zoospores with 2 flagella.
Oospore	Zoosporangia

Herbarium specimen in NIAES

Specimen No.	Scientific name	Host name	Host scientific name	Symptoms	Geographical origin	Collected date	Collector
112-1-121	Sclerophthora macrospora	Barnyardgrass	Echinochloa crus-galli	Downy mildew	Suginami, Kouenji	1928.10.14	Tasugi, H.

(Described by Tsukiboshi, T., NIAES, Microbial Systemtics Lab., 2002)