Describe the change
Unusual spreading masses followed by crusts or tiny fruiting structures.
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.
Organism / cause: Myxomycetes / myxogastrids; not true fungi
Where this evidence applies: Reported on several cultivated mushrooms and substrates; presence does not automatically mean parasitic disease.
Picture → observation → next check
A visual guide to your observations
- Casing layer
For crops that use casing, trace storage, handling and the casing lot separately from the compost.
- Compost below
Compare the compost lot and preparation history. White growth is not, by itself, proof of either purity or contamination.
- Straw bag
Record treatment, cooling, spawning and the first affected position through the intact bag.
- Wood-substrate block
Check the filter, seal and batch history without opening suspect material. Normal block appearance depends on crop and stage.
Keep another explanation open
Fungal colonies, mineral residues and insect deposits.
Collect one useful piece of evidence
Take dated photographs of the same undisturbed area.
A visual match is only a starting point. Specialist examination can separate slime mould from a true fungus and assess whether it caused the loss.
01 · Observe
What you may see
- Unusual spreading masses followed by crusts or tiny fruiting structures.
- Material changing shape or position over time.
No verified reusable diagnostic photograph is included for this entry. The illustration above explains observation context, not a confirmed disease specimen. Consult the original source figures where available.
02 · Compare
What can look similar
- Fungal colonies, mineral residues and insect deposits.
How it may arise or move
Moist organic environments can support these organisms; local ecology and substrate exposure matter.
03 · Check
Collect evidence before changing the crop
- Take dated photographs of the same undisturbed area.
- Note whether mushroom tissue is damaged or only covered.
What confirmation needs: Specialist examination can separate slime mould from a true fungus and assess whether it caused the loss.
Use the field record and sampling checklist →04 · Respond
What to do next
- Keep affected harvest separate and seek identification.
- Do not assume an antifungal product is an appropriate response.
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
- Control avoidable wet residues and keep production surfaces clean.
- Protect substrate and equipment from outdoor debris.
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
2024 literature review; reports differ by organism, host and country.
- Slime molds (Myxomycetes) causing a disease in crop plants and cultivated mushrooms ↗
Frontiers in Plant Science · 2024
Used for: Records across shiitake, Auricularia, Hericium, maitake and other crops.
Limit: Review. These organisms are not true fungi; their presence is not automatically proof of parasitism.
Compare related explanations
Competitor moulds
Mucor/Rhizopus-like pin mould and wet-substrate growth
Upright fuzzy growth with tiny dark heads is an observation to record, not a reliable species identification.
Generic contamination differential, not a proven host disease on all crops.
Signs, checks & response →Fungal diseases
Wood-ear brown rot
A reported Trichoderma-associated rot needs to be separated from natural wood-ear pigmentation, drying and general spoilage.
Confirmed in a particular A. cornea production study; not every brown Auricularia is diseased.
Signs, checks & response →