Black compost

Pythium oligandrum, Pythium hydnosporum

Before applying the casing layer, many mushroom growers have seen areas of compost, black in color and of various sizes and shapes that have not grown with mycelium.

Laboratory researches of this compost have shown that it has been colonized with different kinds of Pythium mold.

Black spots – the areas of compost which have not grown with mycelium

Black spots – the areas of compost which have not grown with mycelium
It was discovered, that problems occur when the spores of this fungus get into the compost either before spawning, or during spawning along with mushroom mycelium.

This mold, which is transferred through soil, can infect straw in the process of grain-crop cultivation or at storing bundles of straw on the ground.

A high content of nitrogen was discovered in areas of compost infected with the black mold. Scientists consider that this happens due to uneven distribution of nitrogen supplements in the compost. But it’s not clear yet whether the areas with a high content of nitrogen restrain the mycelium growth or stimulate Pythium growth.

The other factor that is favorable for the development of this mold is an excessive humidity of the compost.

The following conclusion can be made from the above said: in order to escape the appearance and spreading of the Pythium mold, it is necessary to:

• Avoid the infection of straw through the soil. Bundles of straw have to be stored on a concrete platform;
• Observe the rules of hygiene at unloading pasteurized compost and at spawning;
• Apply and distribute the nitrogen supplements in the compost as uniformly as possible;
• Maintain a corresponding compost humidity.