Peronosclerospora sp. nov. 4

Description

Sporangiophores/Conidiophores not observed.

Sporangia/conidia not observed.

Oogonia formed in the leaf blades which split into a tangled mass of vascular fibres, subglobose-globose, (35-)41-55(-65) µm in diameter; wall (exosporium) polyangular, smooth, 6-32 µm thick, golden brown.

Oospores one per oogonium, globose-subglobose, (26-)29-39(-47) in diameter, adnate with oogonium wall, with a single vacuole; wall (endosporium) 1-4 µm thick, hyaline, even, smooth.

Hosts
   
Host family: Poaceae
   
Host species:

Schizachyrium fragile - BRIP


Distribution

QLD

Comments

This downy mildew is known only from one collection in Queensland, the specimen consisting of a single plant bearing a few frayed leaves. Bonde and Peterson (1981) reported that several species of Schizachyrium (not including S. fragile) were susceptible to a Taiwanese isolate of what they believed to be Peronosclerospora sacchari under artificial inoculation conditions. However, there are no records of a downy mildew pathogen being found on Schizachyrium spp. growing under natural conditions in the World.

Highslide JS
Peronosclerospora sp. on Schizachyrium fragile - BRIP 44244 e.
Scale bar = 1 cm.
Highslide JS
Oospores of Peronosclerospora sp. on Schizachyrium fragile - BRIP 44244 e.
Scale bar = 10 µm.