ABSTRACT
There is still some uncertainty about mushroom virus diseases and the absolute proof that the virus particles seen within the mushroom mycelium, and within the sporophores, are entirely responsible for the symptoms attributed to them has still to be proven. Purified virus preparations have not been introduced into the mushroom and the symptoms reproduced (Koch's postulates - isolation, inoculation, symptom production, reisolation - have not been satisfied). The situation has become somewhat more complex since the discovery of Mushroom virus X disease, because virus particles have not been found, although the genetic material (ribonucleic acid) is present. There is still much to learn about virus diseases of the mushroom. Had current technology been available years ago when Mummy disease and False mummy disease were relatively common, a virus component may have been found in these.
