''Tapesia yallundae'' is the causal agent for a variety of cereal and forage grass diseases. The anamorph of ''T. yallundae'' is the W-type strain of ''Pseudocercosporella herpotrichoides''. The R-type strain of ''Pseudocercosporella herpotrichoides'' is now known as '' Tapesia acuformis''.

Morphology

Produces two types of mycelium - one vegetative, yellow-brown, linear, and branching, the other dark and stromalike. Conidiophores are simple or sparingly branched. Conidia (1.5-3.5 x 37-70 μm) are hyaline, curved, and mostly five- to seven-celled. Sclerotia or sclerotialike stromatic mycelium, at first white to yellow-brown but later dark brown, may also be found on the lesions of infected plants.
Black apothecia, 0.2 to 0.5 mm of diameter, form at the base of host culms. Apothecium contain cylindric to fusoid asci, of 35 to 38 µm x 5.9 to 7.4 µm. Ascospores are hyaline, fusoid, 0-1 septate, with a rounded end and an average size of 8.9 µm (7.4 to 10.3) x 2.07 µm (1.95 to 2.34).

Growth media

''Tapesia yallundae'' can be grown on a moist, sterile wheat and barley straw, oat kernels, and a variety of simple agar media, preferably supplemented with wheat extract. Sporulation in vitro tends to originate from loose sporodochai. Young colonies on potato-dextrose agar are gray, compact and mounded.

Molecular characterization

Polymerase chain reaction (PCR) combined with restriction enzyme digestion of an amplified ribosomal DNA fragment, are now used to characterize ''T. yallundae'' isolates. Novartis produces
polymerase chain reaction (PCR) diagnostic tool
that provides cereal growers with an efficient means for checking the progression of eyespot disease in cereals. The tool reveals the presence and extent of disease before symptoms develop and can identify the different eyespot strains including the W-type (''Tapesia yallundae) and R-type (''Tapesia acuformis'').

Host species

''Aegilops cylindrica''^1,, ''Aegilops ovata''^1,, ''Aegilops'' sp.^1,, ''Aegilops triuncialis''^1,, ''Agropyron cristatum''^1,, ''Agropyron dasystachyum''^1,, ''Agropyron inerme''^1,, ''Agropyron repens''^1,, ''Agropyron riparium''^1,, ''Agropyron'' sp.^1,, ''Avena fatua''^1,, ''Avena sativa''^1,, ''Avena'' sp.^1,, ''Balsamorhiza'' sp.^1,, ''Bromus carinatus''^1,, ''Bromus inermis''^1,, ''Bromus japonicus''^1,, ''Bromus sterilis''^1,, ''Bromus tectorum''^1,, ''Delphinium'' sp^1,., ''Festuca idahoensis''^1,, ''Hordeum distichon''^1,, ''Hordeum vulgare''^1,, ''Koeleria cristata''^1,, ''Lithospermum ruderale''^1,, ''Lomatium triternatum''^1,, ''Poa sandbergii''^1,, ''Poa secunda'', ''Secale cereale'', ''Sitanion hystrix''^1,, ''Trisetum aestivum''^1,, ''Triticum aestivum''^1,, ''Triticum dicoccum''^1,, ''Triticum durum''^1,, ''Triticum monococcum''^1,, ''Triticum'' sp.^1,, ''Triticum spelta''^1,, ''Triticum vulgare''^1,

Notes

1
USDA ARS Fungal Database

Main diseases

Eyespot of wheat; eyespot of barley; eyespot of rye.

Geographical distribution

Notes

1
USDA ARS Fungal Database
br> 2.
3.
4.
5.

Sources

Index Fungorum

USDA ARS Fungal Database

References

{{Authority control Fungal plant pathogens and diseases Barley diseases Wheat diseases Dermateaceae