Efficacy of carboxin and heat treatment for controlling the growth of Sclerotium rolfsii during culture of the mushroom Pleurotus flabellatus

SUMMARY Soaking paddy straw for 18 h in a carboxin suspension in water (5 mg a.i./l) effectively controlled the growth of Sclerotium rolfsii occurring as a natural contaminant in paddy straw, during culture of the mushroom Pleurotus flabellatus. Carboxin at this concentration delayed sporophore formation by 2–3 days, but did not affect total yield. No detectable carboxin residues were found in the mushrooms grown on the treated paddy straw. Treatment of the paddy straw with hot water at 60°C for 10 min completely controlled the contaminant without affecting mushroom growth and yield; but 20 mm treatments with hot air at 60°C or heating with the steam to 75–80°C did not control S. rolfsii.