Management of Bacterial Diseases in Mushrooms

1. Bacterial Blotch (Pseudomonas tolaasii)

Symptoms:

• Yellow-brown, water-soaked lesions or blotches on mushroom caps, especially on Agaricus bisporus (button mushrooms).
• Lesions often become darker, giving the mushroom a discolored, slimy appearance.
• Affected mushrooms may have reduced market value due to blemishes.

Management:

• Sanitation: Disinfect surfaces, tools, and growing areas regularly.
• Proper Ventilation: Maintain good air circulation and reduce humidity to below 85% to inhibit bacterial growth.
• Use of Bactericides: Some growers apply bactericides like chlorine dioxide or hydrogen peroxide at safe concentrations to control bacterial blotch.
• Avoid Overwatering: Keep water application to a minimum, and avoid splashing water on the mushrooms.
• pH Adjustment: Maintain the casing layer pH above 7.0 to make it less conducive for P. tolaasii.

2. Mummy Disease (Pseudomonas agarici)

                                   

Symptoms:

• Affects young, developing mushrooms, causing them to become shriveled, brown, and dry.
• Mushrooms affected by this disease often do not fully develop and have a "mummified" appearance.

Management:

• Improved Hygiene: Strict hygiene during the handling of casing material and in the cultivation rooms.
• Lower Humidity: Keep humidity levels low, especially during the pinning and cropping stages.
• Water Management: Avoid waterlogging and splashing, as wet conditions encourage bacterial growth.
• Use of Clean Casing Materials: Ensure the casing layer is free from contaminants.

3. Brown Center Rot (Burkholderia gladioli pv. agaricicola)

                                   

Symptoms:

• Brownish rot in the center of mushroom caps, often with water-soaked areas.
• The mushrooms may appear slimy and have an unpleasant odor.

Management:

• Sterilization of Substrate: Ensure proper sterilization or pasteurization of substrates to kill bacteria.
• Environmental Control: Maintain optimal environmental conditions, particularly controlling moisture and temperature.
• Water Quality: Use high-quality water with minimal bacterial contamination for irrigation.

4. Soft Rot (Various Bacteria)

Symptoms:

• Soft, mushy decay on the mushrooms, often accompanied by a foul odor.
• Mushrooms may collapse or disintegrate due to bacterial breakdown.

Management:

• Temperature Control: Keep temperatures low to prevent bacterial proliferation.
• Good Hygiene: Clean all equipment and growing areas regularly.
• Water Management: Avoid excessive moisture, as high humidity can exacerbate soft rot issues.

General Management Strategies for Bacterial Diseases in Mushrooms:

1. Hygiene Practices:
• Regular cleaning and disinfection of growing rooms, tools, and surfaces.
• Use of clean water for watering mushrooms and proper sanitation of the water supply.
2. Environmental Control:
• Keep humidity levels below 85%, particularly during periods of vulnerability.
• Maintain proper ventilation to avoid condensation, which can promote bacterial growth.
3. Control of Casing Layer:
• Use sterile or treated casing materials to avoid introducing bacterial pathogens.
• Avoid over-irrigation, especially in the casing layer.
4. Bactericides and Biological Control:
• Some growers use bactericides or biocontrol agents that target specific bacterial pathogens.
• Use of UV-C light to disinfect surfaces and air in the growing area has shown promise.
5. Monitoring and Early Detection:
• Regularly inspect crops for signs of bacterial infection and take immediate action if symptoms are spotted.

Proper sanitation, environmental control, and good cultivation practices are the most effective ways to manage bacterial diseases in mushrooms.