By Dr. Dominic Reisig
Sugarcane aphid was first reported on Johnston grass in the northernmost area of NC during May (click here for article). So it’s no surprise that it has been found on sorghum in both Cleveland and Washington counties this July. Infestations that I saw today in Washington county were at very low levels (see photo) and there were lots of good biological control insects in the field (lacewings and ladybird beetles). Biological control or insecticidal seed treatments will help slow the start of infestations and, in some cases, can keep populations in check to avoid insecticidal treatment. States to our south have reported lower infestation levels compared to previous years and it’s a good idea to wait to treat and use published thresholds (listed below). If thresholds are reached, both Sivanto Prime and Transform are labeled for use in grain sorghum.
| Growth Stage | Threshold |
| Pre-boot | 20% infested plants with localized area of honeydew and established aphid colonies |
| Boot | 20% infested plants with localized area of honeydew and established aphid colonies |
| Flowering-milk | 30% infested plants with localized area of honeydew and established aphid colonies |
| Soft dough | 30% infested plants with localized area of honeydew and established aphid colonies |
| Dough | 30% infested plants with localized area of honeydew and established aphid colonies |
| Black layer | Heavy honeydew and established aphid colonies in head (treat to avoid problems at harvest) |