The greenbug feeds on sap from over 60 species of plants in the grass family. Major hosts are corn, small grains and turfgrasses, including Kentucky bluegrass, annual bluegrass, fescues and perennial ryegrass. Greenbugs live above ground on the grass blades. While sucking out the plant juices from the grass blades, the aphids inject a toxin that kills a portion of the blade around the feeding site. Early damage symptoms consist of a barely detectable yellowing of the turf.
Later damage takes on a characteristic orange to tannish-orange color.
Greenbug damage is usually noticed as large round discolored patches under shade trees, or in the shade along buildings or under shrubbery. However, extensive damage from large populations can occur in full sun. Diagnosing greenbug infestations is fairly simple because of the characteristic color and pattern of the damage. For a positive diagnosis, pull individual green grass blades from the outer edge of the discolored area. The tiny aphids are light green in color and difficult to see, but if present, will be on the upper surface of the grass blade.