There is a good evidence that tabacco necrosis virus, lettuce big vein virus, and tabacoo stunt virus are transmitted by Oplidium brassicae, although absolute proof in aspetic condition is lakcing. Some evidence suggests that polymyxa graminis may be involved in transmission of wheat mosaic virus. One report claims that Synchytrium endobioticum can transmit potato virus X. The cultivated mushroom, Agaricus bisporus, is known to act as a hose of a virus and is apparently involved in the spread of the virus.