Sugarcane aphids are distinct from other common aphids in
sorghum, in part because the cornicles, antennae and feet all have dark tips.
They are often light green to yellowish-whitish-green in color and can be
either winged or wingless.
Winged aphids arrive in fields with the aid of wind, and
founding adults can be found anywhere on the plant. However, populations
usually begin to increase on the undersides of lower leaves in the plant canopy
and then rapidly move up the plant as population size increases.
Sugarcane aphids produce large amounts of honeydew, a
sticky, sugary substance that coats leaves and reflects sunlight. As
populations grow from a single founder event in a field, circles of honeydew-coated
plants often develop. With time and the proper environment, honeydew often
becomes coated with dark sooty mold and infested leaves appear black.
Alatoid nymphs will
soon become winged adults. Photo credit: Patrick Porter.
Typical small
sugarcane aphid colony on the underside of a leaf.
Greenbugs are
frequently found in large colonies on sorghum as well, but they are easily
differentiated from sugarcane aphids because greenbugs have a dark stripe down
the back and do not have dark tips on their cornicles.
Photos modified from originals by Rick Grantham,
Oklahoma State University.
Two other common aphids on sorghum are shown below.
Patrick Porter, Extension Entomologist
