Ink cap fungi (Coprinus or ink weed)

Coprinus spp.

Coprinus spp.
Ink cap fungi appear on the beds before mushroom fruiting. The Coprinus fruit bodies have the shape of a bell on a thin, long stipe. When young, their caps are cream-colored, later, they darken and gradually turn into a mucous black mass. This phenomenon is connected to the development of a great amount of spores which quickly colonize newly-prepared compost. The ink cap fungi mycelium is grey in color and it’s not easy to distinguish it from the mushroom mycelium.

Mycelium and young Coprinus fruit bodies

Coprinus

Coprinus

Young Coprinus growing in the casing layer

Ripe Coprinus

Coprinus, on the last stage of development
Coprinus indicates the presence of free ammonia or conversely, a high content of nitrogen in the compost. The appearance of ink cap fungi in the growing room indicates the low quality of substrate due to the disturbance of the fermentation and the substrate’s pasteurization process.

There are a few reasons:

• The use of bad raw materials: old manure, or manure that has become totally dry after heating, and also straw that is decayed and too old.
• Over humidification of the compost during fermentation or retarded humidification of the compost after its drying.
• The use of excess amount of poultry manure during the composting process.
• Improper execution of the pasteurization process and the disturbance of temperature levels at conditioning.

The basic measures taken in order to avoid the appearance and spreading of Coprinus: strict compliance to the technology of compost preparation and its proper pasteurization.