Pacific Northwest 1998 An Online Guide to Plant Disease Control

FactSheets offer superior print quality for the page you are currently viewing. Using Microsoft's Internet Explorer has given best printing results.
Glossary
Guide Home
Search

OSU Extension Office
 
Blueberry -- Scorch
See Also: Blueberry -- Virus Diseases
 
Cause: The Blueberry scorch virus (BBScV) which is thought to be vectored by aphids and can infect both blueberry and cranberry. Once a plant is infected, symptoms may take 1 to 2 years or more to develop. This makes early detection vital for controlling the disease. The virus was first observed in a Berkeley blueberry planting near Puyallup, Washington in 1980 and has been observed in western Oregon and Washington (near Puyallup and in Clark County), but not northern Washington or in the Fraser River Valley of British Columbia. A recent outbreak of BBScV with more severe symptoms was reported in British Columbia during the summer of 2000. Based on symptoms, it closely resembles the New Jersey strain of BBScV, known there as ‘Sheep Pen Hill Disease’. The identification of this disease in British Columbia has the potential to have a devastating effect on blueberry production in western Oregon and Washington production areas. The New Jersey strain of BBScV causes symptoms in all cultivars except ‘Jersey’, whereas the west coast strain is symptomless in ‘Bluecrop’ and ‘Duke’ as well as several other cultivars. Since BBScV was found throughout the main blueberry production areas of BC, all planting material from BC should be considered suspect and potentially infected with the virus. Quarantines are in effect for Washington and Oregon to restrict the movement of plants from states where the disease occurs.
Symptoms: In spring, shoot tips die back; sometimes on only one or a few branches. Flowers blight just as the earliest ones begin to open. Early symptoms may be confused with bacterial canker or mummyberry. The entire bush becomes infected within 1 to 3 years. Infected plants repeat this symptom cycle each spring. (In contrast, plants infected with the Blueberry shock virus will recover.) Fruit production and shoot growth are markedly reduced on infected plants. Tolerant cultivars may show some yellowing of the leaf margins but no blighting of flowers or leaves.

Notice the flower blight caused by this virus.

 
Cultural control:

  1. Remove any infected plants that show blighting or that test positive for the virus.
  2. Replant with certified virus-tested (and found to be free of all known viruses), disease-tolerant plants. Tolerant cultivars include Bluecrop, Bluetta, Concord, Duke, 1613-A (Hardiblue), Ivanhoe, Jersey, Lateblue, Nelson, Nui, Olympia, Puru, Ranococas and Reka.
  3. Control the aphid vector.
  4. If purchasing plants from BC check to see if they have been tested as free of the scorch virus.
Notes: This disease has a medium risk rating under Agriculture and Agri-Food Canada's Plant Health Risk Assessment for Vaccinium plants and cuttings from the continental United States. There may be a requirement for testing propagation material bound for British Columbia to ensure it is virus-free.
References:
Bristow, P. R., Martin, R. R. and Windom, G. E. 2000. Transmission, field spread, cultivar response and impact on yield in highbush bluebery infected with blueberry scorch virus. Phytopathology 90:474-479.
Content edited by: Jay W. Pscheidt on January 1, 2010
 
Top

In print since 1954 and on the web since 1996. Questions or comments, please contact us.