Greenbug aphid

A small, soft-bodied, pale yellow-green aphid (Schizaphis graminum) with a darker green stripe down the back, found in colonies on the upper leaf blades. Infestations are noticed as numerous tiny aphids on the foliage and as discolored turf, often first appearing under and around shade trees. Confirm by examining leaf blades closely for the clustered aphids.

Like chinch bug injury, greenbug feeding produces brown, irregular patches with distinctive yellow-to-orange or rusty margins as the aphids inject a toxic saliva that causes plant collapse; damage often radiates outward from initial shaded infestation sites.

Greenbug is a true bug (aphid) with gradual metamorphosis. In northern turf it overwinters mainly as eggs glued to grass blades, leaves, and debris; the first spring generation is wingless females that reproduce without mating (live birth), and as many as 15 or more generations can occur per year. Populations build extremely fast in warm spring weather before predators catch up.

Damage occurs mainly in mid-to-late spring when populations explode before natural enemies (lady beetles, lacewings, parasitic wasps) suppress them; it is most common in cool-season turf such as Kentucky bluegrass, tall fescue, and perennial ryegrass, and frequently begins in shaded areas beneath trees. Hot, dry conditions and dense colonies intensify injury.