Japanese Fungi on Plants No.45 before next top

Phytophthora medicaginis Hansen & Maxwell [P. megasperma Drechsler f.sp. medicaginis Kuan & Erwin]
Classification: Oomycota, Oomycetes, Pythiales, Pythiaceae

Widely distributed in Japan. Causes root rot of alfalfa, trefoils and etc. Oospores are produced in the plant tissues and sporangia on the surface of plants. Disperses by zoospores in free water of soil.

Characteristics: Plant pathogen

			Morphology:  Teleomorph: Oogonia spherical, wall thickened, hyaline to pale yellow, 30-32 um in diam., producing oospore not filling oogonia. Antheridia hyaline, spherical to subspherical, 1(-2) amphigynous or paragynous. Oospores germinate directly to produce zoosporangia.  Anamorph: Zoosporangia ellipsoid to oval, hyaline, no apical papillate, 27-63 x 23-38 um, germinating in water to release zoospores with 2 flagella. New sporangia often proliferate extendedly from old ones.
Oospore (Oogonium and antheridium)	Proliferated sporangia

Herbarium specimen in NIAES  None

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

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