Viruses and the Diseases They Cause in Berries

More than 80 viruses infect berry crops. Some of them have a wide host range, such as tomato ringspot virus, which can infect red raspberry, blackberry, strawberry, blueberry, and cranberry as well as grapes, fruit and nut trees, citrus and other crops. Tomato ringspot virus causes severe crumbly fruit and stunting in red raspberry. Other viruses have a very narrow host range, such as blueberry scorch virus, which is only known to infect Vaccinium and Sambucus species. Blueberry scorch virus can cause nearly 100% flower and leaf necrosis in some blueberry cultivars.

 

In many cases, virus diseases in berry crops are caused by a complex of two or more viruses (Martin et al., 2012; Martin and Tzanetakis, 2013). Combinations of different viruses can cause similar symptoms, making diagnosis difficult. For example, blackberry yellow vein disease is caused by virus complexes; there are at least ten viruses that can contribute to this disease. Each of the ten viruses is symptomless in single infections in blackberry. Also, strawberry decline disease is caused by a complex of two to seven viruses.

 

If a plant is infected with just one of these viruses, it often does not show symptoms; it is only in combination with other viruses that disease develops. All of these factors make lab testing critical for an accurate diagnosis.