ABSTRACT
Fungi are the most important group of mushroom pathogens. Fungal diseases can be found to some extent at any time in most countries but their quantity and severity vary. For instance, in the UK Mycogone perniciosa was the most common fungal pathogen in the l950—60 period, followed by Verticillium fungicola var. fungicola from the late 1960s to 1980. In the mid 1980s to the early 1990s, Trichoderma aggressivum caused serious crop losses, and in the mid 1990s Cladobotryum dendroides, a pathogen previously rarely seen causing damage, was frequently epidemic. More recently, Verticillium has again become predominant, although all the others occur from time to time. In the USA, an epidemic of Trichoderma compost mould followed the outbreaks in Europe, and more recently Cobweb disease has caused serious problems on some farms. Similar patterns have been seen in Australia. With the international exchange of materials and greater uniformity of methods, it is possible that the occurrence of mushroom fungal pathogens may become more uniform internationally. There are indications of this already happening with the widespread use of black peat and the occurrence of Cobweb disease in a number of countries.
