Fungicide Sensitivity and Characterization of Cobweb Disease on Pleurotus eryngii Mushroom Crop Caused by Cladobotryum mycophilum

Summary

This research investigated a serious fungal disease affecting commercially grown king oyster mushrooms in Korea. The disease, known as cobweb disease, can rapidly spread through mushroom farms and significantly impact crop yields. The study identified the specific fungus causing the disease and tested various fungicides to find the most effective treatment options. Impacts on everyday life: • Helps maintain stable supply and quality of commercially grown mushrooms for consumers • Provides mushroom farmers with effective disease control methods to protect their crops • Contributes to food security by preventing crop losses in commercial mushroom production • Helps keep mushroom prices stable by preventing large-scale crop failures • Supports sustainable farming practices through improved disease management strategies

Background

Pleurotus eryngii (king oyster mushroom) is one of the most commercially important mushrooms in Korea, accounting for over 30% of the edible mushroom market. In 2009-2010, unusual disease symptoms were observed in P. eryngii grown in mushroom farms in Gyeongnam Province, similar to cobweb disease caused by Cladobotryum mycophilum in other mushroom species. Cobweb disease has previously caused significant crop losses of up to 40% in mushroom cultivation.

Objective

This study aimed to characterize the symptoms of cobweb disease in P. eryngii and evaluate the efficacy of several fungicides in controlling the disease. The research focused on isolating and identifying the causal pathogen, confirming its pathogenicity, and testing fungicide sensitivity.

Results

The pathogen was identified as Cladobotryum mycophilum with 99.5% ITS sequence similarity. The fungus produced cobweb-like growth over mushroom surfaces, with colonies rapidly overwhelming hosts within 3-4 days. Infected areas turned pale brown/yellow and eventually dark brown with rancid odor. Fungicide sensitivity tests showed ED50 values of 0.29-0.31 ppm for benomyl and carbendazim, indicating these were most effective against the pathogen.

Conclusion

Benzimidazole fungicides (benomyl and carbendazim) were found to be most effective against C. mycophilum causing cobweb disease in P. eryngii. However, careful fungicide management is recommended to prevent resistance development. The pathogen can attack at any cultivation stage and spreads rapidly through airborne spores, making it a potentially serious threat to mushroom cultivation.
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