Fungicide resistance among Cladobotryum spp. - Causal agents of cobweb disease of the edible mushroom Agaricus bisporus

Department of Plant Pathology and Microbiology, Horticulture Research International, Wellesbourne, Warwick CV35 9EF, UK
Mycological Research (Impact Factor: 2.81). 03/2000; 104(3):357-364. DOI: 10.1017/S0953756299001197
Source: OAI


A survey of fungicide resistance among isolates of the mushroom pathogens Cladobotryum mycophilum and C. dendroides Types I and II was undertaken, with respect to the active ingredients thiabendazole, carbendazim (benzimidazoles) and prochloraz manganese following an epidemic in Britain and Ireland in 1994/95. The majority of isolates (41/57) were strongly resistant to thiabendazole (ED50 > 200 ppm) and were exclusively C. dendroides Type II. All C. mycophilum and C. dendroides Type I isolates, and four C. dendroides Type II isolates, were weakly resistant to thiabendazole (ED50 1–10 ppm). Thiabendazole-resistant C. dendroides Type II isolates were only weakly resistant to carbendazim (ED50 2–10 ppm) and isolates which were weakly resistant to thiabendazole were carbendazim-sensitive (ED50 < 1 ppm), demonstrating a lack of complete cross resistance between these two benzimidazole fungicides. The ED50 values for all isolates with respect to prochloraz manganese ranged from 0.14 to 7.8 ppm. Benzimidazole resistance was considered to have been an important factor influencing the severity of the 1994/95 cobweb epidemic but 25% of isolates collected were benzimidazole sensitive.

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    • "Cladobotryum dendroides (= Dactylium dendroides ) has hitherto been regarded as the major causal agent of cobweb disease of the cultivated mushrooms (Grogan & Gaze 2000, McKay et al. 1999) and is found in all mushroom-growing countries worldwide (Fletcher et al. 1989, Geels et al. 1988 Harvey et al. 1982). The earliest description of the pathogen was as Botrytis dendroides by Merat in 1821 and later transferred into the genus Cladobotryum making a combination C. dendroides (Bull.: Merat) W. Gams et Hoozem. "
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    ABSTRACT: Cladobotryum species associated with cobweb disease of edible mushrooms were isolated from basidiomata of Agaricus bisporus, Calocybe indica and Pleurotus sajor-caju. Cobweb disease of mushrooms is characterized by the growth of coarse mycelium covering affected mushrooms. The microscopic examination of cultures revealed considerable differences in the fungal morphology but failed to identify Cladobotryum species. The nucleotide sequence comparisons of 5.8S rRNA gene using BLAST network services against NCBI data bases facilitated molecular identification and genetic cataloguing of 15 Cladobotryum isolates into three taxa namely, Cladobotryum dendroides, C. mycophilum and C. asterophorum. The RAPD primers exhibited both inter- and intra-specific variations among the test isolates and separated them into seven distinct phylogenetic sub-clades. Extracellular enzymes assays of ten isolates of Cladobotryum associated with different edible mushrooms revealed variable enzyme activity and it could be observed that higher chitinase and pectinase enzyme assays caused higher yield losses in mushroom crop. The present studies underline the potential threat of cobweb disease in cultivated mushrooms and show significant intraspecific diversity in isolates of all Cladobotryum dendroides, C. mycophilum and C. astropho rum.
    No preview · Article · Dec 2015 · Sydowia -Horn-
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    • "produce masses of spores. Moreover, some species of Cladobotryum from A. bisporus were observed to be fungicide resistant [16] and fungicide application is restricted for edible mushrooms due to its residual toxicity. Disinfection using near-UV irradiation has been described as an effective method for reducing pathogenic fungi and bacteria in mushroom growing spaces [17]. "
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    ABSTRACT: Four Cladobotryum isolates were collected from four different commercially grown mushroom types infected with cobweb disease in Cheongdo-gun and Chilgok-gun of Gyeongbuk Province, Korea in 2010. The isolates were identified as C. mycophilum from Agaricus bisporus and Pleurotus eryngii, C. varium from Flammulina velutipes and Hypsizygus marmoreus. The cultural characteristics of the four isolates were investigated using potato dextrose agar (PDA) media under nine different temperatures ranging from 5~32℃. Rapid growth of the isolates to colony diameters of 47~82 mm was observed at conditions of 18~22℃. No growth was observed at 32℃. C. mycophilum produced a yellowish red pigment while C. varium produced a cream colored pigment after cultivation for 25 days on PDA. Phylogenetic analysis of the internal transcribed spacer region and partial 28S rDNA from the four isolates confirmed they were C. mycophilum and C. varium. Cross pathogenicity tests revealed that the two isolates of C. mycophilum were highly pathogenic toward three mushroom types, but not toward H. marmoreus. The two isolates of C. varium were less pathogenic than those of C. mycophilum, but were pathogenic toward all mushroom types evaluated.
    Full-text · Article · Sep 2012 · Mycobiology
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    • "Numerous species of Cladobotryum cause cobweb disease of A. bisporus (Grogan and Gaze 2000) including C. dendroides , C. mycophilum, C. varium, C. multiseptatum and C. verticillatum (Adie et al. 2006; McKay et al. 1999). In recent years, cobweb diseases have been widespread and caused serious losses in Europe, the USA and Australia (Gaze and Fletcher 2008). "
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    ABSTRACT: This report is the first of cobweb disease on Agaricus bisporus in Korea. Cobweb on both fruit bodies and casing soils were observed on several mushroom farms in Gyeongbuk Province, Korea. Classical and molecular characterization indicated that the causal agent is Cladobotryum mycophilum. The isolated fungus was used to inoculate fruiting bodies of A. bisporus and caused the same symptoms. KeywordsMushroom- Agaricus bisporus -Cobweb disease- Cladobotryum mycophilum
    Full-text · Article · Jun 2010 · Journal of General Plant Pathology
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