Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 2009
Publication Date: August 1, 2009
Citation: Wintermantel, W.M., Gilbertson, R.L., Natwick, E.T., Hladky, L.L., Cortez, A.A. 2009. Epidemiology of Cucurbit yellow stunting disorder virus in California is influenced by an expanded host range of non-cucurbit weed and crop species. Phytopathology 99: S142. Technical Abstract: Cucurbit yellow stunting disorder virus (CYSDV) was identified in the fall of 2006, severely affecting cucurbit production in the southwestern US. Survival of CYSDV through the largely cucurbit-free winter months suggested the presence of weed or alternate crop hosts, although previous studies indicated a limited host range restricted to members of the Cucurbitaceae. To determine potential reservoir hosts for CYSDV in desert production and examine virus epidemiology, weed and crop hosts were collected from throughout California’s Imperial Valley over a period of 26 months, and were tested for the presence of CYSDV by RT-PCR using CYSDV HSP70h- and coat protein gene-specific primers. CYSDV incidence in spring melons was low and limited to a small number of fields, whereas infection of the fall crops was nearly universal. Many non-cucurbits collected from infected melon fields and nearby areas were symptomless and virus free; however, CYSDV was detected in alfalfa (Medicago sativa), lettuce (Lactuca sativa), and snap bean (Phaseolus vulgaris), as well as several weed species widely prevalent in the region. Symptoms of interveinal yellowing and leaf brittleness were observed on CYSDV-infected snap bean, alkali mallow (Sida hederacea) and Wright’s ground cherry (Physalis wrightii), while other infected hosts were symptomless. Transmission tests demonstrated that lettuce, snap bean, alkali mallow, Wright’s ground cherry and buffalo gourd (Cucurbita foetidissima) could serve as virus reservoir hosts. These results greatly expand the previously known host range of CYSDV, demonstrating the virus is capable of infecting not only members of the Cucurbitaceae, but also plants in 6 additional taxonomic families.