Describe the change
Discoloured or deteriorating gills with droplets or exudate.
Bacterial diseases
Drippy gill
The gill surface matters: some disease is hidden beneath the cap. A cap-only photograph can miss the most useful evidence.
Organism / cause: Pseudomonas agarici
Where this evidence applies: Agaricus bacterial gill disease.
Picture → observation → next check
A visual guide to your observations
- Cap surface
Record a local spot versus whole-cap colour, and whether it was present before picking.
- Gills underneath
Separate normal maturity-related pigmentation from unusual wetness, exudate or deterioration.
- Inside the stem
Internal changes can differ from the outside. Obtain sampling instructions before cutting suspect material.
- Casing and compost
Note whether the change starts in the fruit body, the casing surface or the substrate below.
Keep another explanation open
Water droplets after handling and general tissue decay.
Collect one useful piece of evidence
Photograph cap, underside and a comparison mushroom from the same lot.
A visual match is only a starting point. Bacterial isolation and identification distinguish P. agarici from other causes of gill breakdown.
01 · Observe
What you may see
- Discoloured or deteriorating gills with droplets or exudate.
- Damage under the cap that may accompany otherwise less obvious external signs.
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
- Water droplets after handling and general tissue decay.
- Other bacterial damage and old, overmature gills.
How it may arise or move
Bacterial contamination and wet handling conditions should be traced; the precise source needs local investigation.
03 · Check
Collect evidence before changing the crop
- Photograph cap, underside and a comparison mushroom from the same lot.
- Record age, harvest delay, storage and water exposure.
What confirmation needs: Bacterial isolation and identification distinguish P. agarici from other causes of gill breakdown.
Use the field record and sampling checklist →04 · Respond
What to do next
- Hold the affected harvest lot for assessment.
- Do not wash visible symptoms away as a release criterion.
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
- Inspect undersides during quality checks.
- Maintain harvest hygiene and avoid prolonged uncontrolled wet storage.
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
Research on mushroom-pathogenic pseudomonads; phage experiments are not an available cure.
- Genomic Characterisation of Mushroom Pathogenic Pseudomonads and Their Interaction with Bacteriophages ↗
Research article, PMC · 2020
Used for: P. agarici gill disease and P. tolaasii blotch distinctions.
Limit: Experimental phage results are not a farm treatment protocol.
Compare related explanations
Bacterial diseases
Brown bacterial blotch in button mushrooms
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
Bacterial soft rot and tissue collapse
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 →Food & worker safety
Postharvest spoilage, bruising and ageing
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 →