Brown Oyster - Pleurotus cystidiosus

Scientific Name: Pleurotus cystidiosus
Common Name: Maple oyster, Brown oyster

Pleurotus cystidiosus

This mushroom and its close allies have a unique biology and are by far the most interesting of all the Oyster mushrooms. The asexual stage appears to be a "contaminant" to most cultivators. In fact, species in this group are dimorphic - having a sexual and asexual life cycle. A nearly identical species, Pleurotus abalonus, is commercially cultivated in Asia, particularly Taiwan and Thailand. Pleurotus cystidiosus was first described by Dr. Orson K. Miller in 1969 from a maple in Indiana.

Mycelial Characteristics: At first the mycelium resembles any Oyster strain - white, racing linearly, soon fluffy white, and aerial. However, as it grows outwards, black droplets form, radiating outwards from the center as the mycelium matures. These are coremia - stalk-like cells whose tops are fitted with liquid droplets of black spores. The spore-laden black droplets do not pose a contamination threat to other cultures in the laboratory until they dry and harden, at which time they can become airborne. If petri dishes are not handled carefully, the droplets will streak across the media, freeing them. One advantage to the cultivator of this imperfect stage is that inoculation of any substrate with pure culture spawn has an additional complement of asexual spores, effecting a simultaneous "spore mass" inoculation. Colonization is comparatively fast.

Microscopic Features: This mushroom produces white spores.

Suggested Agar Culture Media: Malt Yeast Peptone Agar (MYPA), Corn Meal Yeast Agar (CMYA), Dog Food Agar (DFA), or Potato Dextrose Yeast Agar (PDYA).

Spawn Media: Liquid or grain spawn throughout. Sawdust can be used as the final spawn medium if desired.

Substrates for Fruitings: Sterilized hardwood sawdust (maple, oak, beech, or elm), pasteurized wheat, rice or paddy straw.

Yield Potential: Biological efficiency rated at 50-75%, higher on sawdust based substrates than on straw.

---Growth Parameters---

Spawn Run:

incubation Temperature: 75-85* F (24-30* C)
Relative Humidity: 90-95%
Duration: 12-16 days
CO2: 5000-20,000 ppm
Fresh Air Exchanges: 1 per hour
Light Requirements: n/a
Primordia Formation:

Initiation Temperature: 70-80* F (18-24* C)
Relative Humidity: 95-100%
Duration: 4-5 days
CO2: 500-1000 ppm
Fresh Air Exchanges: 4-8 per hour
Light Requirements: 1000-2000 lux
Fruitbody Development:

Temperature: 70-80* F (21-27* C)
Relative Humidity: 85-90%
Duration: 4-8 days
CO2: <2000 ppm
Fresh Air Exchanges: 4-5 per hour.
Light Requirements: 500-1000 lux
Cropping Cycle:

30 days, two crops, 10 days apart
Comments: With experience with cultures from Thailand and Taiwan, where this group of mushrooms is commercially cultivated, produce abundantly on rice straw and perform less productively on wheat straw. Strains are more narrowly specific in their fruiting requirements, requiring sustained warmth, and must be more carefully matched with the fruiting substrate than, for instance, P. ostreatus, a species more adaptive to a wider variety of materials.

(Information taken from Growing Gourmet and Medicinal Mushrooms, Paul Stamets)