Describe the change
Distinct green growth, sometimes preceded by a soft white patch.
Fungal diseases
Shiitake block green mould
Green mould may damage block colonisation and fruiting. It must not be confused with the normal development of a brown, mature shiitake block surface.
Organism / cause: Multiple Trichoderma species
Where this evidence applies: Lentinula edodes sawdust blocks; log production has a different contamination environment.
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
Normal block browning and maturation.
Collect one useful piece of evidence
Record block age, browning stage and the location of the first patch.
A visual match is only a starting point. A block sample and strain/process history help a laboratory separate competitor identity from physiological maturation.
01 · Observe
What you may see
- Distinct green growth, sometimes preceded by a soft white patch.
- In the cited study, affected blocks became loose and poorly productive.
02 · Compare
What can look similar
- Normal block browning and maturation.
- Dry injury, other competitor colonies or mechanically broken blocks.
How it may arise or move
Contaminated blocks, handling and substrate-processing failures can provide inoculum; species identity cannot be inferred from green colour.
03 · Check
Collect evidence before changing the crop
- Record block age, browning stage and the location of the first patch.
- Compare bag damage, treatment and cooling history with unaffected blocks.
What confirmation needs: A block sample and strain/process history help a laboratory separate competitor identity from physiological maturation.
Use the field record and sampling checklist →04 · Respond
What to do next
- Keep suspect blocks away from handling that exposes clean blocks.
- Do not raise temperature or change pH as an improvised cure based on laboratory growth experiments.
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
- Use suitable spawn, protected cooling and a validated block-production process.
- Separate incubation, fruiting and spent-block handling routes where practical.
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
Chinese research documented several Trichoderma taxa; this is not an India-wide incidence claim.
- Diversity and effect of Trichoderma spp. associated with green mold disease on Lentinula edodes in China ↗
Wang et al., MicrobiologyOpen · 2016
Used for: Shiitake block symptoms and multiple identified Trichoderma taxa; Figure 1.
Limit: Chinese isolates; pH/temperature manipulation is not established as a curative treatment. CC BY.
- 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 →Viruses & culture health
Spawn failure and stalled colonisation
Separate three questions: was the spawn viable, was the substrate suitable, and was the inoculation/handling process sound?
Applies from grain spawn to compost, straw and supplemented wood substrates.
Signs, checks & response →Competitor moulds
Slime moulds: unusual moving or crust-like growth
Slime moulds belong outside the true fungi. They can cover production surfaces or fruit bodies, but interpretation requires more than appearance.
Reported on several cultivated mushrooms and substrates; presence does not automatically mean parasitic disease.
Signs, checks & response →