Does this casing material work? Armillaria mellea


Armillaria mellea is an edible and medicinal mushroom found from spring to Autumn near coniferous or broad-leaved trees. In Asian countries such as China and Japan, the research has been focused on an artificial production of the fruitbodies to secure precious medicinal mushroom resources, with Korea focusing on using sawdust as the main substrate.

The goal of today’s research paper is, therefore, to initiate mass production of Armillaria mellea.

The authors tested seven strains which were cultivated at 25°C (°F) on PDA. The main substrate, here, oak sawdust, was mixed with 30% rice bran and adjusted to a moisture content of 70%. The mixture was filled in bottles and covered with a small amount of ground raw carrots. The bottles were autoclaved for 90 min at 121°C (250°F).

After the inoculation with 10 ml of inoculum, the bottles were incubated at 25°C (°F) in the dark until the mycelium fully colonized the substrate. To initiate the primordia formation, the top of the medium’s surface was scratched slightly and filled with tap water for 3 hours. The bottles were transferred into the fruiting room and maintained at 15 to 17°C (°F) and 80 to 90% relative humidity while applying light for 12 hours.

The authors found that the medium was colonized from top to bottom within 30 days. While the primordia were formed after 10 days of incubation. 7 days later, the fruitbodies reached their maturity with a mean total weight of 24 g per bottle with a range from 2.9 to 59 g per bottle.

The authors compared their results with another research paper and found that their experiment’s probability of producing primordia or fruiting bodies was lower, but the incubation period could be shortened. The shorter incubation period seemed to be the result of casing the substrate with ground raw carrots. Besides, they reasoned that using small bottles compared with large bags, which were used in the other research paper, could also be why the incubation period of their experiment was shorter.

Did the authors reach their goal for mass production?

Yes and no.

Yes, they showed how to reduce the incubation period by introducing a casing layer and using the bottle method.

No, because the probability of producing primordia or fruiting bodies was lower.

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📝Shim JO, Chang KC, Lee YS, et al. The Fruiting Body Formation of Armillaria mellea on Oak Sawdust Medium Covered with Ground Raw Carrots. Mycobiology. 2006;34(4):206-208. doi:10.4489/MYCO.2006.34.4.206