Common name: BlShV
Distribution: The virus primary occurs in the mid-western united states. The virus is not uncommon in Oregon, Washington, and British Columbia. BlShV was also found in Michigan in 2009 and may be preset in Pennsylvania as of 2011. Unfortunately, there are no quarantines for BlShV in NY and PA.
Crops of Concern: Blueberry.
Potential for Economic Impact: Because the virus is pollen-borne, it can spread rapidly within a planting and to neighboring plantings. Given the easy of spread and potential to be vectored by pollinators, the presence of BlShV typically mandates the loss of the affected planting and neighboring blocks in order to mitigate the spread of the virus.
Symptoms/Identification: Flowers and young developing leaves on plants infected with BlShV will rapidly blight at bloom, hence the “shock” designation. Bloom time symptoms will look similar to those of the blueberry scorch virus (BlScV), except that infection is less likely to be immediately lethal to the plants. In fact, infected bushes can experience a flush of growth later in the season and look perfectly normal except that there is often no fruit because the flowers were killed. Moreover, symptoms may only persist for a few years and infections may become quiescent. At this time, the planting is still infectious, and can still transmit the disease to neighboring blocks. Given that the virus is carried in the pollen and vectored by bees during pollination, it is important to remove BlShV infected plantings before bloom. As with other viruses, it is important to only plant certified virus-free stock and avoid planting new blocks near infected fields. To confirm the virus presence, one would need to seek ELISA testing from a diagnostic laboratory.
Monitoring and Management: Watch for a rapid blight of flowers at bloom that is not coincident with a spring freeze. Conduct ELISA testing in the spring/summer, preferentially before bloom.
- Monitoring
- AgDia – testing service
- Cultural Management – Remove and burn infected plants before bloom! Test neighboring plantings and prepare to remove the entire block and potentially neighboring plantings within 500-1000 ft. Purchase certified plants and budwood from a nursery with a virus certification program.
- Chemical Management – There are no means of chemical management for this disease.
Additional Resources: There are several websites that provide more information and excellent descriptions of BlShV.
- Regional Pest Alert: Blueberry Shock Virus – North Central IPM Program
- Michigan Pest Alert: Blueberry Shock Virus – Michigan Department of Agriculture and Michigan State University
- Shock Ilarvirus – Michigan State University
- Blueberry Shock – Pacific Northwest Disease Management Handbook