The complex viral etiology of St. Augustine decline

St. Augustine decline is a viral disease of St. Augustinegrass, a turfgrass grown in the Gulf Coast region of the United States. Analyses of 204 plants in two locations in southeast Texas indicate that the disease is caused by an infection with panicum mosaic virus (PMV), alone or in any combination with satellite panicum mosaic virus (SPMV) and/or its satellite RNAs (satRNAs). This is the first report of the incidence of PMV satRNAs in field samples of St. Augustinegrass. Leaf symptoms of plants collected from the field ranged from severe bleaching to a mild chlorotic mottle, but after 5 months in the greenhouse, the plants had a relatively homogeneous chlorotic mottle phenotype, suggesting that environmental conditions have a significant influence on the development of this disease.