Aspergillus ochraceus K. Wilh.

SRRC 335

Macroscopic characters

Colony diameter after seven days of incubation at 25°C on CYA 40-52 mm; conidia greyish yellow or wheat (4A-B4-5); exudate absent, pale brown or dark orange-brown; reverse red-brown to greyish yellow; soluble pigment absent or slightly brown. Colonies on MEA 45-60 mm in diameter; conidia greyish yellow, light yellow or chamois; exudate absent; reverse brown to yellow brown; soluble pigment absent or colored as reverse. Colonies on CY20S 60-70 mm in diameter; conidia ochraceus (4B5); exudate and soluble pigment absent; reverse brown. Colonies on CZ 20-30 mm in diameter; conidia ochraceus to chamois; exudate absent; reverse red to yellow-brown; soluble pigment absent or slightly pale yellow. Colony diameters on CYA at 37°C 5-30 mm.

Microscopic characters

Stipes 400-1000 um, hyaline to slightly brown, with smooth to rough walls. Vesicles 20-35 um in diameter, globose, hyaline to very pale brown. Aspergilli biseriate. Conidia 2.8-3.5 um in diameter, globose, walls smooth to finely echinulate.

Note

Although this isolate is typical of the species, several related species are morphologically similar. One of the best characters for delineation of species is color of the sclerotia. Unfortunately, many isolates, including this one, do not always produce sclerotia.

Plate 6 Aspergillus ochraceus K. Wilh. SRRC 335

A. Colony on CYA, 7 days at 25°C.
B. Macrograph of the conidial heads showing radiate heads.
C-D. Conidiophores: C. 900x, D. 1600x.
E. Conidia 1400x.

Aspergillus Reference Cultures