Home / Disease library / Button mushroom Find a problem Choose a crop Picture reference Investigate & record Prevent recurrence Sources & limits Crop-specific reading path · Agaricus bisporus
Button mushroom: understand the problem in context. Separate compost, casing, fruit-body and postharvest problems. The timing of the first affected flush and the distribution across beds are often more useful than a close-up alone.
Keep the original cultivation guide open → Three things to record first Record compost supplier/lot, phase-II history, spawn lot and casing lot separately. Inspect caps, stems and gills; record patches before watering or harvesting. For winter huts, include night/day weather swings, leaks, soil contact and fly entry; a controlled-room protocol cannot be assumed. Normal is not always the same across mushrooms White crop mycelium in compost or casing is not automatically cobweb. Brown strains are not automatically brown-cap virus.
Evidence boundary: The deepest disease evidence in this library is for button. Even here, visual resemblance cannot establish the pathogen.
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
Persistent surface wetness can favour bacterial blotch. Managing cap drying means balancing the crop environment, not simply drying the entire room.
Agaricus caps; a brown spot does not establish bacterial identity.
Signs, checks & response → Bacterial diseases
“Ginger blotch” and “yellow blotch” describe appearances, not a dependable field identification of one bacterium.
Blotch-associated isolates from Agaricus in Western European research.
Signs, checks & response → Bacterial diseases
The gill surface matters: some disease is hidden beneath the cap. A cap-only photograph can miss the most useful evidence.
Agaricus bacterial gill disease.
Signs, checks & response → Bacterial diseases
A mushroom can look relatively normal outside while its stem is damaged internally. Internal quality checks can reveal a different problem from cap blotch.
Reported in cultivated Agaricus; stem browning has multiple possible causes.
Signs, checks & response → Bacterial diseases
Mummy describes a recognisable crop syndrome, but the label should not hide uncertainty about cause.
Agaricus production syndrome.
Signs, checks & response → 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
Poor cropping and malformed mushrooms can justify virus testing, but neither an image nor a low yield confirms a virus.
Agaricus virus investigation; symptoms are not specific.
Signs, checks & response → Viruses & culture health
Virus detection is not automatically proof that the detected virus caused the symptoms. Mixed infections complicate interpretation.
Unexpected browning in a normally white strain and associated crop disorders; normal brown strains are not this disease.
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
Tiny larvae in wet crop material can be overlooked when a farmer only watches for flying adults.
Historical Indian pest group; local identification is essential.
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
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
A dense surface mat is not automatically a contaminant. Separate crop mycelium from advancing foreign growth and review the stage transition.
Cased crops; do not apply casing-based terminology to uncased oyster bags.
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
An infection whose appearance changes with the age of the mushroom when it is attacked. A distorted pin and a spotted mature cap can belong to the same disease.
Principally cultivated Agaricus; do not transfer the diagnosis to every malformed mushroom.
Signs, checks & response → Fungal diseases
A disease of developing mushroom tissue, often producing swollen, disorganised masses rather than a normal cap and stem.
Agaricus disease; the two names occur in different publications.
Signs, checks & response → Fungal diseases
Spreading surface growth can overrun casing and fruit bodies. The important clue is progression across the crop, not simply white colour.
Strong Agaricus evidence; additional cultivated hosts are documented in Korean studies. Susceptibility varies with isolate and host.
Signs, checks & response → Fungal diseases
A competitive or pathogenic fungus can occupy compost that should be colonised by the mushroom. Green spores may appear after an initially white phase.
Composted Agaricus substrate. Not every green colony is the aggressive epidemic organism.
Signs, checks & response → Fungal diseases
Hairlike growth on mushrooms can be mistaken for cobweb. The cap tissue and the stage at which the growth appeared both matter.
Reported in Agaricus crops and after harvest.
Signs, checks & response → Competitor moulds Competitor moulds
An Indian seasonal-production problem worth investigating when yellow colonies accompany poor compost colonisation.
Agaricus compost; “yellow mould” is a group description, not one confirmed organism.
Signs, checks & response → Competitor moulds
A competitor recorded in Indian mushroom research. Unusual compact fungal bodies in compost deserve identification rather than a “mushroom” label.
Historical Agaricus problem; this is not an edible truffle crop.
Signs, checks & response → Competitor moulds
Old farm manuals use colour and texture names. They are useful search terms, but a visible colony rarely supports a species-level diagnosis.
A historical-name register, not proof that every organism occurs on every listed crop.
Signs, checks & response → 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 → Crop-specific sources Control of Fungal Diseases in Mushroom Crops while Dealing with Fungicide Resistance: A Review ↗ Gea et al., Microorganisms 9:585 · 2021
Used for: Dry bubble, wet bubble, cobweb and green mould; Figure 1 reference photographs.
Limit: Review, not a local diagnosis. Fungicide approvals and resistance vary by country. Photographs retained with CC BY attribution.
Seeding Substrate and Management of Growing Agaricus bisporus ↗ Penn State Extension · 23 December 2025
Used for: Spawn run, substrate heat, moisture and mummy-risk context.
Limit: Agaricus substrate management is not a sterilisation protocol for supplemented sawdust bags.
Basic IPM: Bacterial and Viral Diseases of Mushrooms ↗ Penn State Extension · 8 July 2021
Used for: Mummy and La France recognition and exclusion.
Limit: Symptoms overlap with stress. Broad historical bacterial attribution does not establish a unique mummy pathogen.
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 .