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POSTERS: Pathogen dispersal and survival

Epidemiology of Cotton leaf roll dwarf virus in Georgia, USA
Nabin Sedhain - University of Georgia. Jared Whitaker- University of Georgia, Robert Kemerait- University of Georgia, Sudeep Bag- University of Georgia, Phillip Roberts- University of Georgia, Peng Chee- University of Georgia

During 2018-19, Cotton leafroll dwarf virus (CLRDV) has been reported from the southern United States in Alabama, Florida, Georgia, Mississippi, and South Carolina. This phloem restricted virus, transmitted by aphids in a persistent, circulative and non-propagative manner. Since January 2019, in coordination with UGA-Extension, an extensive survey is initiated in GA to investigate the alternate hosts that could potentially act as a green bridge. Different weeds commonly found in GA including HenBit deadnettle (Lamium amplexicaule), Mouseear chickweed (Cerastium vulgatum), Purple cudweed (Gnaphalium purpureum), Curly dock (Rumex crispus), Carolina Geranium (Geranium corolinianum) and Wild radish (Rhaphanus raphanistrum) were collected from commercial cotton fields. In addition, cotton stalks and leaves regrowth from the remains of the previous year crop were also sampled. The samples were analyzed using RT-PCR to detect the presence of the virus. The virus is detected from the cotton stalk, suggesting its overwintering host as well. Cotton being a perennial crop and could survive the winter as a reservoir. Proper sanitation measures, like roughing, or plowing needs to be included for the management of the virus to break the disease cycle. The economic impact of the virus and sanitation practice is to be investigated. Processing of the weeds and other hosts is underway. These results could help us develop an appropriate management strategy for this emerging virus disease.