A few sugarcane aphids (SCA) have been found feeding on sorghum around Itasca as of Friday. Aphid numbers are very small, on less than 1% of plants with only one or two aphids per colony. The rain this week will likely slow their population growth, and typically populations only reach damaging levels around boot or flowering. These small, isolated populations are not concerning, but scouting should continue on a regular basis. SCA were found last year as early as May 29th.
Above is a picture (taken last Friday on milo) of a sugarcane aphid in a colony of yellow sugarcane aphids. Treatment thresholds are different for each aphid, so it is important to know the difference. Yellow sugarcane aphids (YSCA) have also been seen in small numbers. YSCA inject a toxin as they feed, while the sugarcane aphid does not. Just one or two YSCA can cause a leaf to die, turning purple or yellow, due to the toxin (second picture). As of now, YSCA populations are not concerning, and have been seen on around 2% of plants.