Viruses in Cranberry
Year 2018 Information about Tobacco Streak Virus (TSV) and Blueberry Shock Virus (BlShV) which have been found in cranberries in Massachusetts and Wisconsin (we are being watchful in Maine):
- Both TSV and BlShV manifest themselves by deep grooves on the berries (similar to Bravo® injury and sometimes to hail damage as well).
- Both are very spotty on a bed (nobody has seen them on a whole bog as yet).
- TSV affects berries that are on the same runner, and nearly always it’s every berry on every upright coming from the infected runner (suggests that TSV is a systemic type of infection). This ‘is’ the case for BlShV.
- Flower and tip blighting are also observed sometimes on TSV-infected uprights (less common than the berry scarring).
- Both TSV and BlShV overwinter and persist in the vines from year to year.
- The cranberry plants recover from both TSV and BlShV by the time berries are formed in the subsequent season after being infected (no visual symptoms or observed negative side effects but the virus is still in them).
- TSV is spread (probably) by thrips (thrips do spread it in other crops), and possibly by way of pollinators carrying the infected pollen around.
- BlShV is spread by seeds and has been found in seedlings that grow from infected seeds.
- BlShV has not been detected in lowbush blueberry as yet.
- Most of the BlShV infections have been found in mature beds of ‘Stevens’ (and some in Mullica Queen, Norman LeMunyon, and Pilgrim).
- No cure, currently, for the viruses.
- Scout for signs of the virus by looking for prematurely red berries during early fruit set, although cranberry fruitworm will cause that as well.
Additional/Detailed Information (with photos):