National mushroom virus survey - update

The vast majority of mycoviruses – the viruses which are naturally widespread throughout both cultivated and wild fungi – cause no problems to their host.  But occasionally, combinations of virus particles interact, causing quality and yield issues. 

Pathogenic viruses can be hard to detect in mushroom crops. They can replicate unseen and undetected, establishing large disease reservoirs on-farm.  Early symptoms can go unnoticed or be ignored. For example, sporadic brown mushrooms appearing in white button crops being dismissed as just ‘one of those things’. 

The delay in identifying the causal ‘organisms’ was one of the key factors leading to the devastating impacts of MVX Syndrome in Europe. Early detection and appropriate intervention is key to successfully mitigating the effects of these serious pathogens.

Australia has a long history of virus disease.  La France was first recorded in this country in 1969 and there have been sporadic damaging outbreaks recorded over the years. 

In 2021 a farm reported a disorder expressing La France-like symptomology. However, samples sent to an external diagnostic laboratory did not detect the La France virus.  A second sample was tested for Mushroom Virus X (MVX) Syndrome viruses. This test detected the AbV6 virus particle, which is associated with MVX Syndrome. 

A preliminary survey of mushrooms from supermarkets, together with selected farm samples, provided results consistent with the findings from the farm outbreak samples.  After consultation with Dr Helen Grogan (Teagasc in Ireland, the leading authority on MVX Syndrome), and discussions with the MU16003 project reference group, it was decided to offer a nation-wide survey to the industry to determine the extent of virus contamination in Australian button mushroom crops.

Read the full report from the Pest and Disease Team, Dr Warwick Gill and Judy Allan in MushroomLink Issue 2