Dr. Ames Herbert confirmed the presence of sugarcane aphids, Melanaphis sacchari, in a sorghum field at the Tidewater Agricultural Research and Extension Center in Suffolk, Virginia, on Sep. 17, 2015. Sugarcane aphid spreads as winged adults on wind and storm fronts so infestations can spread rapidly–so to be on the safe side, sorghum fields should be scouted.
There are several other aphid species that can infest sorghum but sugarcane aphid can be differentiated from the others being smooth, cream yellow, with two, short dark cornicles (“tailpipes”) on the hind end.
Research by Mike Brewer, Texes AgriLife, and David Kerns, LSU, has provided the most up-to-date Econominc Injury Level (EIL) of 50 to 125 aphids per leaf at sorghum prices of $4/bu; and the currently recommended Economic Threshold (when the insecticide needs to be applied to prevent the population from reaching the EIL) of 25 – 30% infested plants with 50 aphids per leaf.
After heading, according to work in other states, one of the more effective insecticide products is Sivanto (Bayer CropScience). Please refer to the Section 2(ee) Recommendation for the lower (but effective) rate of Sivanto @ 4-7 oz/A here (please take note of the pre-harvest intervals and other directions found in the Section 2(ee)).