Scorch And Shock: Emerging Virus Diseases Of Highbush Blueberry And Other Vaccinium Species

Authors: Martin, Robert; BRISTOW, P - WASHINGTON STATE UNIV; WEGENER, L - SIMON FRASER UNIV

Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: 2/8/2006
Publication Date: 8/31/2006
Citation: Martin, R.R., Bristow, P.R., Wegener, L.A. 2006. Scorch And Shock: Emerging Virus Diseases Of Highbush Blueberry And Other Vaccinium Species. Acta Horticulturae. 715:463-467.

Interpretive Summary: The purpose of this presentation is to review and update information on Blueberry scorch virus (BlScV) and Blueberry shock virus. BlScV was first characterized in 1988 and subsequently it was shown that Sheep Pen Hill Disease of blueberry in New Jersey was caused by a strain of BlScV. In 2000, BlScV was detected for the first time in British Columbia, Canada and has since been found to be widespread in blueberry plantings there. It was found in the Netherlands in 2002 and in Italy in 2005. The virus can be transmitted by several different aphids under experimental conditions but the vector(s) that are important for transmission in the field are not known. The virus infects cranberry without causing symptoms. There are seven strains of BlScV reported from British Columbia suggesting this may be the center of origin for this virus. Blueberry shock virus (BlShV) was first reported in 1991 in Washington and Oregon and has continued to spread in Oregon, Washington and British Columbia since that time. It has not been reported from other blueberry production areas. It is pollen-borne, and plants show a severe shock reaction (dieback of flowers and leaves) the first one or two years after infection but do not show any symptoms in subsequent years, and the recovered plants produce a full crop. The industry in the Pacific Northwest is interested in the possibility of having plants propagated from infected mother plants to produce plants that will not go through the shock reaction once they are planted. Other viruses of importance in blueberry, including Tomato ringspot, Tobacco ringspot, Blueberry shoestring and Blueberry leaf mottle, will be discussed along with a few viruses of minor importance.

Technical Abstract: Blueberry scorch virus (BlScV) was first characterized in 1988 and subsequently it was shown that Sheep Pen Hill Disease of blueberry in New Jersey was caused by a strain of BlScV. After that, there was not much interest in the virus until the mid 1990’s when blueberry scorch disease became increasingly important in New Jersey. In 2000, BlScV was detected for the first time in British Columbia, Canada and has since been found to be widespread in blueberry plantings there. The virus can be transmitted by several different aphids under experimental conditions, but the vector(s) that are important for transmission in the field are not known. In 2003, it was discovered that cranberry is a symptomless host for BlScV. It appears that there are significant biological differences between some strains of BlScV especially with respect to symptoms in many cultivars. The NW type strains do not produce visible symptoms in many cultivars, whereas the EC strains cause leaf and flower blighting in most cultivars other than ‘Jersey’. Blueberry shock virus (BlShV) was first reported in 1991 in Washington and Oregon and has continued to spread in Oregon, Washington and British Columbia since that time. It has not been reported from other blueberry production areas. It is pollen-borne, and plants show a severe shock reaction (dieback of flowers and leaves) the first one or two years after infection but do not show any symptoms in subsequent years, and the recovered plants produce a full crop. Other viruses of importance in blueberry, including Tomato ringspot, Tobacco ringspot, Blueberry shoestring and Blueberry leaf mottle, will be discussed along with a few viruses of minor importance.