Describe the change
White growth followed by green sporulation in compost or casing.
Fungal diseases
Green mould in button compost
A competitive or pathogenic fungus can occupy compost that should be colonised by the mushroom. Green spores may appear after an initially white phase.
Organism / cause: Trichoderma aggressivum and other Trichoderma species
Where this evidence applies: Composted Agaricus substrate. Not every green colony is the aggressive epidemic organism.
Reference image only. These are published study examples, not photographs of your crop or claims about an Indian outbreak.
Picture → observation → next check
Read the picture with the evidence
Keep another explanation open
Penicillium, Aspergillus and other green-sporing contaminants.
Collect one useful piece of evidence
Compare compost, spawn and filling dates between affected and unaffected rooms.
A visual match is only a starting point. Laboratory identification is needed for species attribution. Green colour alone cannot diagnose T. aggressivum.
01 · Observe
What you may see
- White growth followed by green sporulation in compost or casing.
- Weak crop colonisation or unproductive patches around affected substrate.
02 · Compare
What can look similar
- Penicillium, Aspergillus and other green-sporing contaminants.
- Poor spawn run caused by heat, ammonia or unsuitable compost.
How it may arise or move
Contaminated substrate, equipment and operations around spawning can introduce or distribute the organism; later handling moves spores.
03 · Check
Collect evidence before changing the crop
- Compare compost, spawn and filling dates between affected and unaffected rooms.
- Review actual substrate-temperature records, not only room-air readings.
What confirmation needs: Laboratory identification is needed for species attribution. Green colour alone cannot diagnose T. aggressivum.
Use the field record and sampling checklist →04 · Respond
What to do next
- Restrict disturbance and movement of suspect compost.
- Escalate repeated batch-linked losses to the compost/spawn supplier and an independent diagnostic adviser.
These are investigation and containment steps, not a guaranteed cure. Do not eat, sell or distribute suspect material on the strength of a visual match. Do not culture unknown contaminants or experiment with pesticides in a growing room.
05 · Learn
Reduce recurrence
- Maintain clean spawning and filling operations.
- Verify the compost process and post-treatment protection rather than adding an unvalidated “mould cure”.
After intervention, compare new affected units, crop condition and inspection results against the same recorded baseline. A lack of visible growth does not, by itself, verify decontamination or food safety.
Read the stage-by-stage prevention plan →Evidence & sources
Established production problem; organism-level conclusions require testing.
- Green Mold of Mushrooms ↗
Penn State Extension · Updated 23 December 2025
Used for: Green mould in commercial Agaricus production.
Limit: US production context. Green colour does not identify Trichoderma species.
- Molecular Approaches for Detection of Trichoderma Green Mold Disease in Edible Mushroom Production ↗
Biology · 2023
Used for: Detection limits and reported hosts including milky, paddy straw and Ganoderma.
Limit: Host reports do not show prevalence in every Indian region; molecular identification needs qualified interpretation.
Compare related explanations
Fungal diseases
Green mould in oyster and other bags
A bag can contain competing mould before green colour is visible. Oyster-associated Trichoderma species differ from the main button-mushroom epidemic species.
Detailed pathogen evidence exists for Pleurotus; the other listed crops have published green-mould host reports, not a shared diagnosis.
Signs, checks & response →Competitor moulds
Aspergillus, Penicillium and unidentified green moulds
Green, blue-green or dark growth is not automatically Trichoderma. Neither harmlessness nor toxin production can be established from its colour.
Raw-material, spawn, substrate and storage contamination differential across production systems.
Signs, checks & response →Environmental disorders
Ammonia, waterlogging and unsuitable substrate
Poorly colonised substrate can be a process failure before a competitor arrives. Treating the visible late mould may miss the original cause.
Ammonia/conditioning is especially relevant to button compost. Bag substrates use different preparation systems.
Signs, checks & response →