Olive green mold

Chaetomium spp.

Olive green mold is seen pretty often. In its presence in the compost, the reduction of mushroom yield happens proportionally to the degree of the mold growth. When compost is severely infected and the mold rigorously grows in it in a short period of time after pasteurization, a satisfactory yield cannot be expected.

Olive green mold in a bag of compost

Olive green mold in the compost on its initial stage
The olive green mold mycelium is grayish-white in color and it can be mistaken for mushroom mycelium on an early stage of growth. After some time, fruit bodies the size of a pin and the shape of olive green pustules appear on the white, fluffy mold. They darken in time, and the compost in these areas becomes black and smells musty and damp. Olive green mold can appear on the casing surface or inside it. There’s also a kind of Chaetomium mold creamy and grey in color. Spores, which form on pustules, are easily carried by wind, insects, personnel’s clothes and other objects.

Olive green mold progressing in the compost
Olive green mold serves as an indication of low quality compost. The main reason for its appearance is the remaining amounts of ammonia after pasteurization or newly formed ammonia.

Ammonia can remain in the compost:

• when pasteurization is carried out in a very short period of time;
• at high fluctuations in temperature during the pasteurization process;
• at insufficient aeration during pasteurization;
• at a very high temperature of pasteurization (above 62°C);
• when anaerobic conditions are created during pasteurization because of a high compost filling consistence or an excessive humidity of phase 1 compost;
• at the application of an excessive amount of nitric supplements, especially ammonia sulfate and urea;
• when poultry manure of low quality is used (in big clumps) and when the mixture is poorly mixed at compost preparation.

The means of olive green mold control are unknown. Therefore, all measures must be taken in order to prevent its appearance. This means:

• the compliance by the technology and the preparation of high-quality phase 1 compost with a good structure, normal humidity level and balanced C/N ratio;
• carrying out compost pasteurization properly;
• maintaining hygiene on the farm.