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How to identify it
- Adults are 1.3 to 2.0 mm long and usually lemon to bright yellow, sometimes straw-colored or pale green.[1][2]
- Two double rows of dark spots run down the top of the abdomen, with more rows of spots along the sides.[1][2]
- The body is covered with short, stiff hairs or spines, and the cornicles (the paired 'tailpipes') are reduced to short, slightly raised pores.[1][2]
- Winged adults have the same spotted yellow abdomen with a darker head and thorax.[1]
- Colonies line up along the veins on the undersides of leaves.[1]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Sugarcane aphid | Pale yellow, gray or tan with black feet, antennae and cornicles.[2] |
| Greenbug | Light green with a dark green stripe down the back rather than bright yellow with spots.[2] |
| Corn leaf aphid | Dark green and usually feeds in the whorl of the plant.[2] |
Where it lives
Thought to be native to North America, it occurs across temperate and subtropical North America, including Hawaii, north to New York and Washington, as well as in the Caribbean and Central and South America.[1]
Biology and life cycle
In warm climates females reproduce without mating and give birth to live young; where winters are cold, females mate with wingless males. Nymphs pass through four stages, with no pupal stage.[1]
The aphids tolerate crowding and usually move to other leaves only after the leaf they are on has turned mostly yellow and started to die.[1]
Hosts include sorghum, sugarcane, corn, rice, wheat, barley and many lawn and pasture grasses such as johnsongrass, dallisgrass, Paspalum, Panicum and Digitaria species, as well as some sedges.[1][2]
Earwigs, about 10 kinds of lady beetles, flower fly larvae, predatory ants including the red imported fire ant, and young spiders can sharply reduce populations, though not always before damage is done. Parasitic wasps rarely attack it.[1][2]
Temperatures above 95 F and heavy summer rains also knock populations down. In Florida most damage occurs in spring and mid to late fall.[1]
Damage and signs
- The aphid injects a toxin as it feeds. Depending on the host and temperature, leaves turn yellow or red; on sorghum seedlings they turn purple and growth is stunted.[1][2]
- Prolonged feeding kills leaves early and can kill plants or sugarcane stalks. In sorghum, damage often delays maturity and leads to lodging, which stalk rots can make worse.[1][2]
- Seedlings are most vulnerable: an infestation of a week or less can badly damage sorghum with one to three true leaves, and in sugarcane the loss of as few as two lower leaves in the first three months can cut yield by 6 percent.[2][1]
- It also transmits sugarcane mosaic virus.[1]
Health risk
It is a crop and grass pest; neither source describes any risk to people or pets.[1][2]
Control
Prevention
Resistant varieties are an important tool. Many sorghum varieties are susceptible, but resistant sorghum and sudangrass hybrids are grown in Florida for grazing and silage, and in 2005 UF/IFAS reported sugarcane clones under development with at least partial resistance.[1]
Traps and physical control
Scout sorghum from the first week after emergence, twice a week, until plants have at least five true leaves. Purple seedlings can signal an infestation, but root injury, phosphorus deficiency and cold, wet or compacted soil can also turn leaves purple, so look for the aphids.[2]
Biological control
Monitor populations to see whether predators are keeping numbers low enough to prevent early leaf yellowing and death before deciding to treat.[1]
Pesticides
Texas A&M lists neonicotinoid seed treatments (clothianidin, imidacloprid, thiamethoxam) and labeled foliar insecticides, with treatment thresholds for seedlings based on the percentage of plants infested. Timing is critical, because by the time discoloration shows the plants are already significantly injured.[2][1]
Common questions
- Why are my sorghum seedlings turning purple?
- Yellow sugarcane aphids are one cause: their toxic saliva turns seedling leaves purple and stunts them. Root injury, phosphorus deficiency and cold, wet or compacted soil can do the same, so check leaf undersides for small, spotted yellow aphids.[2]
- How is the yellow sugarcane aphid different from the sugarcane aphid?
- The yellow sugarcane aphid is bright yellow with rows of dark spots and short cornicles; the sugarcane aphid is pale yellow, gray or tan with black feet, antennae and cornicles.[2]
- Does it feed on lawn grasses?
- Yes. Besides crops, it reproduces on lawn and pasture grasses.[1]
Sources
- University of Florida IFAS Extension (EDIS), “Yellow Sugarcane Aphid, Sipha flava (Forbes) (EENY-354/IN635).” journals.flvc.org/edis/article/view/115132 (accessed 2026-11-09)
- Texas A&M AgriLife Extension Service, Department of Entomology, “Sorghum management guide: Stem- and Leaf-Feeding Insects.” extensionentomology.tamu.edu/resources/management-guides/sorghum/stem-and-leaf-feeding-insects/ (accessed 2026-11-09)
- iNaturalist, “Sipha flava taxon page (order and family).” www.inaturalist.org/taxa/454650 (accessed 2026-11-09)