Our first confirmed identification of white sugarcane aphid occurred this week. A BIG thanks to Laura Siegle in Amelia County for her vigilance and sharp eye.
What does this mean for sorghum growers? It is time to scout. At least once per week until aphids are spotted in the field. Following that and until threshold is met – scout twice per week. Numbers can increase quickly.
Start scouting on the borders of fields. Aphids will infest borders first. Check the underside of leaves. Not every aphid you find is a sugarcane aphid. You can bring samples to me or your local agent.
Corn earworm are likely found in sorghum this time of year. The same products will not kill both sugarcane aphids and corn earworm. Only Transform and Sivanto Prime are labeled for white sugarcane aphids in Virginia.
Scout for earworms by beating sorghum heads into a 10-gallon bucket. A rough threshold is 2-4 worms per head. A threshold that includes costs of application and sorghum prices can be found here.