Colonies on agar Chapek with yeast extract (CYA) 3-4 cm in diameter on the 7th day, velvety, rarely woolly, with white or grayish mycelium and varying intensity of sporulation in gray or gray-brown tones. Often a bright yellow soluble pigment is released. Reverse taupe. At 37 ° C, colonies 3-5 cm in diameter, similar to colonies formed at 25 ° C, or with a more pronounced brown tint in sporulation. On malt extract agar (MEA), colonies are 4-5 cm in diameter on the 7th day, velvety or woolly, abundantly spore in olive brown tones. The reverse is greenish or brown.
The conidiophore heads are two-tiered, with a brown leg 100-300 microns long, with spherical to hemispherical apical bloating up to 7-16 microns. Metulae covering the upper two-thirds of the swelling, 4-7 microns in length. Violets 5-7 microns long. Conidia are spherical, rough to coarse, 3.2-4.5 microns in diameter.
Differences from close species
It is determined by the grayish color of sporulation and conidiophores with small bunk heads with small apical swellings.
A widespread species, often isolated from soil and from various plant substrates in temperate regions of the world.
One of the relatively few species of the genus that can grow at +5 ° C.
Aspergillus ustus ( Bainier ) Thom & Church , The Aspergilli 152 (1926). - Sterigmatocystis usta Bainier , 28: 78 (1882).