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POSTERS: Population biology and genetics

Incidence of bacterial and viral diseases in blueberry in Maryland.
Ramesh Pokharel - Maryland Dept of Agric. Robert Martin- USDA ARS

Blueberry growers in Maryland have expressed concern with increasing incidence of diseases, especially those caused by viruses and some bacteria, and their impact of sustainable production. Due to confusing visual symptoms in plants and lack of information on their occurrence, a survey was initiated in 2018, we collected 109 blueberry leaf samples from June to September at seven farms located throughout Maryland. These samples were tested for six viruses of concern in blueberry including: blueberry leaf mottle virus (BLMoV), blueberry scorch virus (BlScV), blueberry shock virus (BlShV), blueberry shoestring virus (BSSV), tomato ringspot virus (ToRSV), tobacco ringspot virus (TRSV), and Xylella fastidiosa (XF) using ELISA kits developed by different companies. Twenty-two additional samples were collected from two out of original six sites, in late October, 2018. These samples were tested for the above viruses as well as for blueberry fruit drop associated virus, blueberry necrotic ring blotch associated virus, blueberry red ringspot virus, blueberry virus A and blueberry mosaic associated virus, by RT-PCR and PCR. Three viruses and XF were recorded in a few blueberry samples during the survey by ELISA: BLMoV, BSSV, and ToRSV. None of the samples collected in October and tested by PCRs were positive for any of the viruses or XF. It is possible that sampling late in October leads to false negatives, thus comparisons will be done multiple times during the 2019 season. Further study of the incidence of plant viruses in berry crops is underway.