Since eight years new disease symptoms are occasionally causing problems in mushroom cultivation, especially in the United Kingdom.
The Horticultural Research Institute (HRI) has demonstrated that these symptoms are caused by one or more viruses. Discoloration of the button mushrooms is the only symptom in the Netherlands. The seriousness of the symptoms differs per culture.
Detection of the virus
Fungal viruses consist of doublestranded ribonucleic acids (dsRNAs). PRI Mushrooms has available an efficient method for the extraction, purification and visualization of these dsRNAs with
gel analysis. This method yields a banding pattern that is characteristic of one or more viruses. Only the smaller dsRNAs are related to the browning of the mushroom caps. The larger bands can also found in cultures without symptoms.
The bands are therefore divided into symptomatic bands and non-symptomatic bands.The seriousness of the symptoms differs per culture.
A sensitive test for symptomatic dsRNAs
PRI Mushrooms has developed a sensitive test to determine whether the viral dsRNAs are always present in commercial button mushroom cultivars or that they originate from infection. This test is 1000 times more sensitive than the above-mentioned gel analysis. The test shows that low concentrations of symptomatic dsRNA are sometimes also present in white button mushrooms without symptoms.
A first screening of cultures, however, shows that symptomatic dsRNA is fairly rare in cultures without symptoms. This seems to indicate that infection plays an important role in the transmission of this disease.
Earlier research of HRI has shown that the symptoms during the different stages of the culture and a low degree of infection are transferable. Hygiene is therefore very important in preventing infection and spreading.
PRI is together with HRI developing tests for other viral dsRNAs. The tests will be used to discover the origin of the viruses and to measure the effects of hygienic measures.