Sugarcane Aphid Management on Sorghum
The sugarcane aphid was found severely damaging sorghum in Georgia in August 2014 and rapidly spread throughout central and southern Georgia over the next two months, with about 90 percent of sorghum fields being infested. UGA entomologists conducted field trials in Georgia to evaluate the efficacy of currently registered and selected new insecticides for control of sugarcane aphid. These trials and insecticide trials showed that two new insecticides, Transform 50WG (sulfoxaflor) and Sivanto prime (flupyradifurone), were the most effective products. Registered insecticides such as the pyrethroid insecticides were not effective and chlorpyrifos (Lorsban other names) and dimethoate (Cygon) provided only marginal control. Transform, a product of Dow AgroSciences, is not labeled on sorghum. A section 18 emergency use exemption for sulfoxaflor (Transform WG) was prepared for use on sorghum in Georgia over the past four seasons. The exemptions were approved by the Georgia Department of Agriculture and sent forward to US-EPA where it was approved in each year. Most of the estimated 25,000 acres of sorghum in Georgia in 2017 were treated at least once with Sivanto prime or Transform WG to control the sugarcane aphid and some fields were treated two to three times. No effective insecticides are legally available for use on sweet sorghum and many sweet sorghum fields were a complete loss in 2015 and 2016. A section 18 emergency use exemption for was obtained for Sivanto prime for sweet sorghum for 2017. This prevented severe losses to sweet sorghum in 2017. The estimated cost of insecticides for sugarcane aphid control in each of the past three years exceeded $1 million each year. But this control saved sorghum growers several millions of dollars in losses that would have occurred without effective control measures.