Allen Knutson, AgriLife Extension entomologist in Dallas. And Jim Swart, Extension IPM specialist in Commerce, agree that the sugarcane aphid poses a much greater threat to Northeast Texas sorghum fields this year than it did last summer when it showed up too late to cause much damage.
Sugarcane aphids are a light green and somewhat yellowish in color, Knutson says. “It’s very tiny; a colony the size of nickel will typically be comprised of 30 or 40 individual aphids. It’s unlike any of the other aphids we have in sorghum.”
Damage results from aphids feeding on plant sap. The fed-upon leaves discolor, turning yellow, red, and brown. Extensive leaf injury can greatly reduce grain yield. The honeydew poses a risk to harvest machinery.
“Infestations can increase very rapidly, so fields should be inspected every three to four days to determine if an insecticide treatment is needed,” Knutson says.
Swart says about one-third of Northeast Texas sorghum fields have reached treatment thresholds. “I hope we don’t have to spray all our fields,” he says.
Transform WG insecticide has been approved under a Section 18 Special Exemption to treat sugarcane aphids in Texas.