White sugarcane aphid was found last week in South Carolina sorghum and this week as far north as Florence in North Carolina. This insect is threatening sorghum production in Texas and the mid-South. We need to be on the lookout in North Carolina all the way through harvest to determine if this insect is here. Note that there are many native aphid pests of sorghum so it is important to know what you might be fighting. Please read on for information on identification and management.
The white sugarcane aphid recently made a host switch to sorghum. This new behavior has caught everyone off guard and has the potential to hit us in North Carolina. Why is this insect so bad? Before sorghum heads it can kill or stunt plants, prevent heading, or reduce head size. After sorghum heads up until harvest, it can prevent equipment from harvesting by plugging it with honeydew (from the aphids). This insect breeds extremely rapidly.
Once you have the insect, it can blow up in a few days. Weekly sampling intervals need to be shortened for proper management. Finally, it is very difficult to manage with registered insecticides. The only effective registered insecticide we have in North Carolina is Lorsban, which has a 60 day pre-harvest interval restriction. Other states have applied for a Section 18 exemption to register Transform. Until we detect the insect in our state, we will not have this option.
White sugarcane aphids are yellow and can be distinguished from other aphids in sorghum by the presence of black tailpipes on the tail (cornicles) and black feet below their yellow legs. These aphids will often infest entire fields, which is rare for our native aphids and are especially a problem behind sprays for other insects that might kill beneficial insects.