Home / Disease library / Shiitake Find a problem Choose a crop Picture reference Investigate & record Prevent recurrence Sources & limits Crop-specific reading path · Lentinula edodes
Shiitake: understand the problem in context. Begin by stating whether the crop is on outdoor logs or supplemented sawdust blocks. Their contamination, maturation and pest exposure are different.
Keep the original cultivation guide open → Three things to record first Record block browning and maturity before fruiting. On logs, record wood species, inoculation history, soaking and outdoor feeding damage. Compare green colonies with normal brown block surfaces. Normal is not always the same across mushrooms Block browning is a normal maturation feature; it is not the same as a green sporulating patch.
Evidence boundary: Trichoderma research and outdoor-pest guidance are available. Not every log-associated fungus isolated in a paper is proven to cause every farm failure.
Read the relevant condition guides These links are a differential list, not a claim that your crop has all these diseases. Each entry states whether it is an established host report, a regional study or a generic process/safety risk.
Bacterial diseases Viruses & culture health Pests & vectors Environmental disorders Food & worker safety Fungal diseases Competitor moulds Bacterial diseases Bacterial diseases
Wet, collapsing tissue is a reason to separate produce and investigate timing. It can be a primary infection or secondary decay after injury.
Symptom differential. The cited Burkholderia evidence includes Agaricus bitorquis; it is not the cause of every soft rot on this crop list.
Signs, checks & response → Viruses & culture health Viruses & culture health
A clean-looking culture can lose desirable fruiting behaviour. Conversely, a failed crop does not prove that the strain has genetically degenerated.
Detailed research cited for Cordyceps militaris; other crop filters indicate a culture-quality investigation, not the same mechanism.
Signs, checks & response → Viruses & culture health
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 → Pests & vectors Pests & vectors
Adults are a monitoring clue. Larvae feeding in substrate, pins or mushrooms cause the direct crop damage.
Production-system risk across crops; most detailed guidance cited concerns commercial Agaricus.
Signs, checks & response → Pests & vectors
Phorids must be distinguished from sciarids because monitoring and biological-control choices are not interchangeable.
Strong commercial Agaricus context; other crops require identification of the actual fly.
Signs, checks & response → Pests & vectors
Some mites damage crops or carry contaminants; others feed on mould or other small organisms. Their presence may point to an underlying contamination problem.
A small moving speck is not enough to identify a harmful mite.
Signs, checks & response → Pests & vectors
Crop decline in wet substrate may justify examination for nematodes, but the presence of nematodes alone does not establish the cause.
Nematode function depends on identity; not all are harmful to mushrooms.
Signs, checks & response → Pests & vectors
Jumping specks and surface grazing require identification and evidence of damage. Not every organism found near a crop is its primary problem.
A broad pest differential, especially where substrate contacts soil or wet organic residues.
Signs, checks & response → Pests & vectors
Missing tissue is not necessarily disease. Feeding, physical damage and contamination by animals require different responses.
Outdoor/log cultivation and entry into protected farms; exact risks vary with location.
Signs, checks & response → Pests & vectors
Identification can prevent the removal of useful organisms. Biological control still needs the correct pest, product, conditions and local legal status.
A decision guide, not an instruction to release an unapproved organism.
Signs, checks & response → Environmental disorders Environmental disorders
Interpret shape against the intended crop. Air exchange, carbon dioxide, light and crowding interact; a single photograph cannot choose a ventilation setpoint.
Species and strain matter: a shape desired in enoki or king oyster may be undesirable in another crop.
Signs, checks & response → Environmental disorders
Room humidity does not tell the whole water story. A crop can have wet caps in one rack zone and drying injury in another.
All production systems, with different crop-specific tolerances.
Signs, checks & response → Environmental disorders
A room-air reading can miss a hot substrate core. Equally, a cold chain suitable for button mushrooms must not be assumed suitable for paddy straw.
Substrate, crop and storage temperatures must be interpreted separately for each species.
Signs, checks & response → Environmental disorders
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 → Environmental disorders
Unexpected forms or lesions after cleaning, spraying or nearby fuel use need an exposure history as well as a disease differential.
Rosecomb is classically described in Agaricus; broader crop filters cover exposure investigation, not identical symptoms.
Signs, checks & response → Environmental disorders
Counting days is not the same as checking readiness. Poor fruiting can follow immature substrate, an unsuitable transition, culture quality or infection.
Species-specific induction and fruiting systems, including cased and uncased crops.
Signs, checks & response → Food & worker safety Food & worker safety
Separate when damage started from when someone noticed it. That distinction prevents a storage problem being mislabelled as a growing-room disease.
Harvest, packing, transport and storage; a crop can deteriorate after leaving a healthy room.
Signs, checks & response → Food & worker safety
A healthy-looking mushroom is not proof of food safety. A crop-disease photo guide cannot detect Listeria, Salmonella or unacceptable residues.
All edible-mushroom food chains; enoki outbreak evidence is a specific example, not a claim about every crop.
Signs, checks & response → Food & worker safety
Removing a mouldy crop must not create a dust cloud. The work method and source control are central to protecting people.
Substrate preparation, harvesting, waste handling and cleaning can create different exposures.
Signs, checks & response → Fungal diseases Fungal diseases
Green mould may damage block colonisation and fruiting. It must not be confused with the normal development of a brown, mature shiitake block surface.
Lentinula edodes sawdust blocks; log production has a different contamination environment.
Signs, checks & response → Competitor moulds Competitor moulds
Rapidly spreading orange growth is an operational contamination problem. A history of food use for selected Neurospora strains does not make an unknown colony safe.
Generic substrate-contamination differential; not a confirmed disease report for every crop listed.
Signs, checks & response → Competitor 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 → Competitor moulds
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 → Competitor moulds
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 → Crop-specific sources 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.
Forcing Bolts: Common Mushroom Pests and Concerns ↗ Cornell Small Farms · Undated guide
Used for: Outdoor shiitake slug, beetle and wildlife observations.
Limit: Some controls are grower anecdotes; do not introduce livestock into food-production areas on that basis.
A reference, not a diagnosis. Photos and symptoms narrow the questions; they do not confirm an organism, a safe food lot or a pesticide choice. This is a source-linked editorial synthesis. Independent specialist review of this new library is not yet recorded. Research checked 2026-09-20. Read the evidence limits .