Fungal diseases in mushrooms: Dry Bubble disease

The signs of Dry Bubble disease can vary, depending on when the infection happens in the crop’s development. Find out what the symptoms look like and how the disease spreads.

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Symptoms of Dry Bubble disease

There are several signs to watch out for.

In the early stages of infection, you may notice:

  • Small bubbles of tissue developing
  • Split stipes (stalks) and partial malformations

In older developing mushrooms, keep an eye out for wart-like growths on the cap. On fully formed mushrooms, which may get infected through watering or transmission from flies, you may notice grey-brown spots on the caps.


How Dry Bubble disease spreads

The spores in Dry Bubble disease are sticky, which means they attach to everything they touch. The first infection in a mushroom crop usually happens when the casing or casing equipment is contaminated. This can happen through contact with:

  • Wind-blown dust
  • Flies
  • People
  • Water splashes

Single pieces of Dry Bubble will appear in the crop. If they are not treated, they will produce masses of spores and continue the spread of infection.


Treating the disease

  1. Clearly mark all the areas you are going to treat.
  1. Don’t remove any pieces of bubble, even with disposable gloves, as you’ll risk spreading the sticky spores further.
  1. Dampen some strong, double thickness paper tissue and cover the affected area with a border of at least 5 cm.
  1. If there are growing mushrooms beneath the paper, try to break the connection with the casing to stop growth.
  1. Check the areas regularly to make sure there has been no regrowth nearby.

If you notice dry bubbles, spots and misshapen mushrooms spreading over a large area, it means an undetected piece of Dry Bubble was watered over at the end of the previous flush, spreading the infection.

If this happens:

  • Cover the area as before and consider terminating the crop at the end of the flush
  • Don’t water it again if taking to another flush
  • Review your hygiene procedures and make sure they’re being followed

Useful links

Download a factsheet on Dry Bubble disease in mushrooms

Other fungal diseases: Wet Bubble Disease

Other fungal diseases: Cobweb Disease

Learn how to manage fungal diseases in mushrooms

Images are courtesy and copyright of INAGRO and Teagasc

Wart-like growths on mushrooms

Dry bubble disease symptoms: wart-like growths


Grey-brown spots on mushrooms due to water splash

Dry bubble disease symptoms: grey-brown spots due to water splash

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