St. Augustine decline (SAD) in a lawn. St. Augustinegrass and centipedegrass are the only turfgrasses that this virus is known to affect. Disease is often associated with plant stress caused by drought and inadequate fertilizer. St. Augustine decline in the early stages of infection. Leaf blades show a chlorotic mottling or stippling. As the mottling progresses, leaves develop a chlorotic appearance. Early stages of SAD are often confused with iron chlorosis. Iron deficiency initially appears in the younger/new leaves and is characterized by yellow stripes parallel to the mid-vein of the leaf blade. SAD infestation results in the mottling of both young and old leaves.

St. Augustine decline virus is mechanically transmitted by mowing equipment and other tools. Cleaning the equipment with a 10% bleach solution can reduce the spread of the virus.