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moderate

Bacterial Blotch

Pseudomonas tolaasii

Bacterial infection causing discolored, slimy spots on caps. Common when water sits on mushrooms.

Reference Images

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What It Looks Like

Yellow-brown slimy patches on mushroom caps, especially after water sits on surface

Recommended Action

Affected mushrooms are cosmetically damaged but safe to eat if caught early. Improve air circulation and misting technique.

How to Identify
  • 1Yellow to brown discoloration
  • 2Slimy/sticky texture
  • 3Appears where water pooled
  • 4Affects caps more than stems
  • 5Mushroom is still safe if caught early
Common Causes
  • Water droplets sitting on caps
  • Direct misting of mushrooms
  • High humidity without air movement
  • Harvesting with wet hands
Prevention Tips
  • Never mist directly on mushrooms
  • Mist walls and floor instead
  • Maintain air circulation
  • Harvest with dry, clean hands

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