Bahiagrass Susceptibility to Barley Yellow Dwarf Virus.

Studies conducted at the North Florida Research and Education Center (NFREC) at Marianna and the Range Cattle Research and Education Center, Ona, Florida, documented plant stunting and reddened leaves occurring sporadically in diploid populations of bahiagrass ‘Pensacola’, ‘Tifton 9’, ‘TifQuik’ and ‘Sand Mountain’ (P. notatum Flüggé saurae) and consistently in apomictic, tetraploid bahiagrass cultivars ‘Argentine’ and ‘Paraguay 22’ (P. notatum Flüggé). Plant nutritional status and exposure to cold temperatures were initially investigated as possible reasons for the symptoms expressed, but were ruled out as the causal agent(s). Preliminary results implicate bahiagrass as a host of BYDV, transmitted by aphids. Both tetraploid and diploid cultivars are susceptible, but the virus incidence was more apparent in tetraploid types and only sporadic in the diploid cultivars. Because of the widespread use of bahiagrass as improved pasture in the southern Coastal Plain of the U.S., the success of cultural control methods would likely be ineffective. Delaying planting small grains, particularly susceptible oats, until cold weather prevails, may slow the movement of the aphids transmitting the virus. Through conventional and molecular plant breeding, selection of bahiagrass lines tolerant or resistant to the virus may be a possibility, once the mode of infection, vector investigation and plant disease reaction are fully studied.