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ARS Home » Research » Publications at this Location » Publication #221983

Title: Blueberry Red Ringspot Observations and Findings in North Carolina

item Polashock, James

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/8/2009
Publication Date: 3/1/2009
Citation: Cline, W.0., Ballington, J.R., Polashock, J.J. 2009. Blueberry Red Ringspot Observations and Findings in North Carolina. Meeting Abstract. 810:305-312

Interpretive Summary:

Technical Abstract: Observation of suspected blueberry red ringspot virus (BRRV) prompted an extensive survey of fields at the 50-acre NCSU Ideal Tract blueberry farm, and of commercial farms in surrounding counties. Polymerase Chain Reaction (PCR) testing with red ringspot-specific primers was used to confirm the presence of the virus in samples with typical and non-typical symptoms. Over 15,000 plants were surveyed visually, with PCR used for backup confirmation. The virus was detected primarily in highbush (Vaccinium corymbosum) and southern highbush seedlings, selections and cultivars. Incidence was low. Spread occurred primarily by propagation, but rare, widely scattered infections in older fields suggested an infrequent or inefficient winged vector. Hundreds of rabbiteye (V. virgatum, syn V. ashei) bushes were also surveyed, but symptoms were not observed on any rabbiteyes. Random samples from rabbiteye were negative in PCR testing. Symptoms were observed, and confirmed by PCR, from three surrounding counties, including wild or feral blueberries adjacent to commercial fields. Symptoms were first seen in early June, became progressively more noticeable from June through August, and included red rings on leaves, stems and fruit. Scattered to numerous red rings (3-6 mm) with green or pale green centers were the most frequent symptom on leaves, usually visible only on the upper leaf surface. Larger (5-15 mm) red rings or spots were visible on stems of the current season’s growth. Most cultivars/clones had few or no fruit symptoms; only ‘Ozarkblue’ produced distorted, unmarketable fruit on infected bushes. Some infected seedlings and selections appeared to be stunted. The virus has also been reported from Georgia; in this study, two southern highbush cultivars (‘Star’, ‘Misty’), reportedly from a Georgia nursery source, were symptomatic and tested positive for the virus. Studies beginning in 2008 will assess possible seed transmission, possible vectors, and determine incidence and severity in the southeastern US.