Volume 11 Part 1 Article 53: The Control of Bubble Diseases of Agaricus bisporus (Lange) Imbach

Volume 11 Part 1 Article 53
Year 1981
Title: The Control of Bubble Diseases of Agaricus bisporus (Lange) Imbach
Author: J.T. Fletcher


Diseases caused by the fungal pathogens, Verticillium fungicola (Preuss.) and Mycogone perniciosa (Magn.) are commonly referred to as dry and wet bubble respectively because of the bubble-like shape of the distortions of severely affected sporophores. Bubble diseases occur in all countries where there is a significant mushroom industry although they fluctuate in their incidence. In England a survey of mushroom diseases in 1964 (Anon, 1964) showed that M. perniciosa was relatively common compared with V. fungicola. Between 1964 and 1970, V. fungicola increased in incidence and in 1969 was causing concern on many farms. The recommended fungicidal treatment for both of the diseases has included the use of one of the dithiocarbamates (Yodder, Sinden and Hauser, 1950), and in particular mancozeb which was the most effective although not giving comnlete control especially if inoculum levels were high (Fekete and Kühn, 1967).

The introduction of the benzimidazole fungicides in 1969 had a major effect on disease control. Early work had shown that fungicides such as benomyl and thiabendazole were very effective for the control of bubble diseases (Snel and Fletcher, 1971), and these results were later confirmed by workers in various countries (Holmes, Cole and Wuest, 1971; Gandy, 1972; Nair and Baker, 1978) . Generally, the control of M. perniciosa was better than that of V. fungicola. Even in the absence of diseases some strains of Agaricus bisporus were shown to yield better following applications of benomyl (Wuest, Cole and Patton, 1972). A second, and in the longterm, more important effect of the high standard of disease contirol achieved with the benzimidazoles was the relaxation of hygiene standards on many farms. Where, before, it had been necessary to use very strict procedures, including the employment of personnel whose sole job it was to remove diseased mushrooms, the low levels or even absence of bubble diseases (and cobweb caused by Hypomyces rosellus) made such procedures unnecessary. The change in attitude of many growers was one of the major factors which affected the incidence of V. fungicola in the years that followed the period of effective control.

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