🍄 Button Mushroom Casing, Harvest, IPM and Quality

Why This Lesson Is Advanced

Most button mushroom losses happen after the basic crop is already established: casing dries out, CO2 remains high, bacterial blotch develops, flies enter the room, or harvest handling bruises caps. This lesson focuses on those management details.

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Casing Quality

ICAR mushroom research highlights casing as a prerequisite for button mushroom because it supports primordia formation, acts as a water reservoir, protects mycelium, and physically supports fruit bodies.

Desired casing property	Why it matters
High water-holding capacity	Prevents drying of pins.
Porosity	Maintains gas exchange.
pH 7.0-7.5	Favours button mushroom pinning.
Low soluble salts	Prevents mycelial stress.
Pasteurised material	Reduces moulds, nematodes, and flies.

Coir pith, loam, FYM, spent mushroom substrate, lime, and sand can be combined to mimic peat-like casing properties where peat moss is unavailable.

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Pinning Troubleshooting

Symptom	Likely cause	Correction
No pins after casing	High CO2, high temperature, dry casing, poor casing microbes	Increase ventilation, lower temperature, maintain casing moisture.
Long stems, small caps	Excess CO2	Improve fresh air exchange.
Brown blotches on caps	Free water on cap surface; bacterial blotch risk	Water earlier, ventilate, avoid wet caps overnight.
Uneven crop	Uneven spawn mixing or uneven casing moisture	Improve mixing and misting uniformity.
Mould patches	Poor pasteurisation or hygiene	Remove infected area, improve sanitation.

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Pests

Pest	Exam clue
Sciarids	Fungus gnats; larvae damage mycelium and spread diseases.
Phorids	Scuttle flies; rapid runners, disease carriers.
Mites	Feed on mycelium and fruit bodies.
Springtails	Small jumping insects in moist substrate.
Nematodes	Damage mycelium and reduce yield.

Sanitation, fly-proof netting, clean spent-compost disposal, and pasteurisation are more important than late chemical control.

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Major Diseases

Disease	Common clue	Key idea
Dry bubble	Brown spot, deformed dry caps	Caused by Lecanicillium fungicola (formerly Verticillium fungicola).
Wet bubble	White mould, soft distorted masses	Caused by Mycogone perniciosa.
Cobweb disease	Grey-white web over casing/mushrooms	Spreads fast in high humidity.
Green mould	Green competitor patches	Commonly associated with Trichoderma.
Bacterial blotch	Brown sunken blotches on caps	Favoured by wet caps and poor ventilation.
False truffle	Truffle disease	Competitor fungus in compost/casing.

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Harvest and Post-Harvest Quality

Button mushrooms are harvested when caps are still closed. After harvest they respire rapidly, lose water, bruise easily, and brown quickly.

Practice	Why it matters
Twist, do not pull roughly	Protects casing and neighbouring pins.
Trim dirty stem base	Improves market grade.
Avoid washing before storage	Extra surface water increases bacterial blotch and spoilage.
Cool quickly	Slows respiration and browning.
Grade by size and colour	Higher market price for clean white buttons.
Process surplus	Canning, drying, pickling, powder, soup mix.

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Mushroom Poisoning Safety

Poisonous mushrooms can cause:

1. Gastric disorder
2. Nervous disorder
3. Muscular disorder
4. Haemolytic disorder

For public education, teach this plainly: cultivated mushroom supply is safer than wild collection because visual identification by non-experts is unreliable.

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Summary Points

Concept	Key detail
Casing role	Water reservoir, gas buffer, microbial pinning trigger, physical support.
Long stems	Excess CO2.
Bacterial blotch	Wet cap surface + poor ventilation.
Dry bubble	Brown spot / distorted dry caps.
Wet bubble	White mould / soft masses.
Green mould	Competitor mould, commonly Trichoderma.
Harvest stage	Closed button stage.
Poisoning types	Gastric, nervous, muscular, haemolytic.