The invasive weed Ventenata dubia is a host of Barley yellow dwarf virus with implications for an endangered grassland habitat

Ventenata dubia (African wiregrass), a winter annual weed, is a non-native species invading grasslands, rangelands and pastures throughout the USA. Limited information is available on its suitability as a host to pathogens and insects in its invaded range. The barley/cereal yellow dwarf virus (B/CYDV) complex occurs ubiquitously in Poaceae species. In non-managed grasslands, BYDV infection influences competitive dynamics between native and invasive grasses and facilitates invasion by non-native annual weeds. The Palouse prairie of south-eastern Washington and northern Idaho, USA, is an endangered ecosystem. Surveys of V.dubia in Palouse prairie and neighbouring Conservation Reserve Program (CRP) habitats were conducted to determine whether B/CYDV viral species are present. Laboratory tests examined the suitability of V.dubia to host BYDV-PAV and serve as an inoculum source. Plant growth and weight parameters were measured to gauge the impact of BYDV-PAV on V.dubia. Infection of V.dubia in Palouse prairie and CRP habitats with two species of BYDV, PAV and SGV, was detected for the first time. The ability of BYDV-PAV to infect V.dubia in the laboratory and transmission from infected V.dubia to barley were demonstrated. BYDV-PAV-infected V.dubia showed reductions in plant height, number of leaves and tillers per plant, and above-ground dry weight, suggesting that V.dubia is sensitive to BYDV. Results demonstrate that V.dubia is a host to BYDV and may serve as a virus inoculum source with potential implications for its management, competitive dynamics between invasive and native grasses and future conservation of endangered grasslands.