Mushroom disease library · Field companion
Investigate a mushroom crop problem
A step-by-step field record, symptom comparison and laboratory handoff. Observe safely, preserve batch history and ask the right diagnostic question.
First, protect people and preserve the evidence.
If a person has breathing difficulty or another urgent health problem, seek medical help. A crop guide cannot diagnose a person. If a food lot may be unsafe, hold distribution while the responsible food-safety professional assesses it.
For the crop, avoid opening, smelling, brushing or shaking contaminated material. Mark the room, rack and batch. Tell the supervisor before routine watering, picking or waste movement can alter the pattern.
Do not switch off necessary ventilation or add disinfectant to a living crop as an automatic first reaction. Containment must fit the room and the suspected problem.
Follow the evidence, not the colour.
- Where?
Room → rack → bag/bed → cap/stem/gills. Take a wide view before the close-up.
- When?
First observation, crop stage and last normal inspection. Keep dates, not only “three days ago”.
- Which pattern?
One patch, a substrate lot, a watering path or an entire room? Record affected and checked units.
- What changed?
New spawn, casing, water, cleaning product, climate event, worker route or packing delay?
A symptom can have several explanations
Use this table to choose your next check, not to make a final diagnosis.
| Observation | Possible explanations | Useful next question |
|---|---|---|
| White fluffy growth | Normal crop mycelium, cobweb, pin mould, early Trichoderma | Where did it start? Is it advancing over fruit bodies? Do not disturb it to see whether spores fly. |
| Green patch | Trichoderma, Penicillium, Aspergillus or another mould | Record the first white/coloured stage, bag opening point and preparation batch. Colour cannot name the species. |
| Brown cap or spot | Blotch, bruising, strain colour, virus-associated brown cap | Whole-cap colour or local lesion? Present before picking? What cultivar and wetness history? |
| Misshapen mushroom | Bubble disease, virus, air/light/water stress, normal strain form | Look at crop stage, affected tissue and room-wide pattern. Compare a healthy same-strain unit. |
| Wet/slimy collapse | Bacterial rot, temperature injury, late secondary decay | When did it start: growing room, packing or transport? Hold affected produce. |
| Tiny moving organisms | Flies/larvae, mites, springtails, nematodes | Record movement, location and crop damage separately. Ask for identification before control. |
| No pins or slow growth | Immaturity, substrate failure, contamination, culture decline | Compare culture lot, substrate lot and stage conditions; do not change everything at once. |
A field record you can print or copy
Keep the record with the original, unfiltered photographs. Use your browser’s Print command for a paper copy. This page does not upload or save your farm data.
- Identity
- Farm contact, location, crop species/strain, room, rack and batch identifier.
- Dates and stage
- Spawning, bag opening/casing, induction, first harvest, first symptom and last normal check.
- Inputs
- Spawn supplier/lot, substrate ingredients and treatment, compost/casing lots, water source.
- Observation
- Cap, stem, gill, casing, substrate or container; colour, texture, progression and affected area.
- Extent
- Affected units / inspected units, locations, neighbouring units checked and how selection was made.
- Environment
- Time-stamped room and substrate readings, cap wetness, watering, ventilation changes and calibration checks.
- Recent events
- Power loss, heat/chilling, floods/leaks, new products, pest entry, shared tools and waste movements.
- Harvest and actions
- Lots held/dispatched, people informed, actions already taken, products used and results so far.
Example calculation: 8 affected bags among 100 inspected bags is 8% of that inspection sample, not automatically 8% of the farm. Record the sampling method and include zero/new cases on later checks.
Prepare photographs a specialist can use
- Context: show the whole bed, rack or group of bags so the distribution is visible.
- Unit: photograph the intact affected bag or fruit body with a batch identifier and a scale placed safely nearby.
- Detail: capture the affected surface under neutral light. Avoid beauty filters, oversaturated colour and digital “enhancement”.
- Comparison: include a healthy-looking unit of the same strain and stage. Label it as a comparison, not a laboratory-certified healthy control.
- Progress: revisit the same marked position at the next safe inspection. Do not move exposed contamination to improve the picture.
If an underside or cut surface is required, ask how to obtain it without spreading material. Never culture unknown contaminants at home to create a better picture.
Contact the laboratory before collecting a sample
ICAR–DMR lists crop-health identification and substrate-related testing among its services. A KVK, agricultural university or qualified mushroom diagnostic service may help direct the enquiry. A website listing does not guarantee that a particular sample or test will be accepted.
- Describe the question: identification of a fungus/insect, a bacterial differential, a specific virus test, substrate condition, water quality or food safety. These are not the same analysis.
- Ask what is needed: material type, quantity, comparison sample, container, labelling, preservation, shipping temperature, delivery window, fees and authorised recipient.
- Follow their collection method: do not add disinfectant, freeze, mix samples or send exposed sporulating material unless specifically instructed through an appropriate procedure.
- Interpret the report: ask whether it identifies an organism, establishes likely causation or merely detects its DNA. Ask what a negative result can and cannot exclude.
For a suspected food-safety incident, contact the competent food-safety professional or authority rather than assuming a crop-pathology test is sufficient.
- Services available ↗
ICAR–DMR Solan · Site update 1 September 2026
Used for: Lists insect, pest and disease identification and compost/casing testing.
Limit: Confirm sample acceptance, charges, contact person and transport instructions directly before sending anything.
- Basic IPM: What is Integrated Pest Management? ↗
Penn State Extension · 8 July 2021
Used for: Monitoring, identification, prevention and evaluation.
Limit: US organic approvals and economic thresholds do not automatically apply in India.
- 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.
When to escalate promptly
- Rapidly expanding symptoms, repeated batch failures, unusual mortality of pins or an unexplained change across rooms.
- A problem following one spawn/input supplier lot or recurring after crop-end cleaning.
- Suspected virus disease, unresolved identification or a result that conflicts with the observed pattern.
- Worker illness, possible unsafe food, chemical exposure or affected produce already dispatched.
The responsible adviser should agree containment, treatment eligibility, disposal, restart criteria and follow-up. This library cannot set a universal crop-destruction threshold or certify a room ready for refill.