The effect of amount of water used to irrigate casing soil on the development of bacterial diseases of the white button mushrooms

The most common bacterial diseases of mushrooms are the brown blotch caused by Pseudomonas tolaasii and the ginger blotch caused by Pseudomonas ‘gingeri’. Protection against bacterial infections consists in ensuring an appropriate microclimate in the cultivation rooms. The aim of the study was to assess the severity of bacterial blotch symptoms depending on the amount of irrigating water of mushroom cultivation. The crop was infected with a suspension of bacterial cells as equivalent to the application of 2.6 × 107 and 2.6 × 108 cells per 1 m2 of casing surface. The crop was watered in a fixed amount, i.e. 7, 10 and 14 litres per m2 of casing before the first flush and 6, 8 and 10 litres before the second flush. It was found that the amount of water had a significant impact on the severity of ginger blotch, especially in the first flush. The yield of infected mushrooms was significantly higher in the cultivation watered with the highest amount of water than in the other variants of the experiment. In the case of P. tolaasii statistically insignificant amount of infected mushrooms was observed in the cultivation with the highest amount of irrigating water. The severity of disease symptoms and the amount of water used to irrigate casing soil were highly or moderately correlated with each. It has been shown that a properly conducted watering treatment reduces the development of bacterial blotches on mushrooms.