b"TAKINGACTION AGAINST SORGHUM APHIDSFighting back on the farm with genetic resistance.Melissa ShipmanTHERE IS GOOD NEWSand bad news for sorghum grow-ers. The good news is that they no longer need to worry about sugarcane aphid. The bad news is that they do need to continue protecting their sorghum crops against aphid: what was previously thought to be sugarcane aphid in sorghum crops actually is sorghum aphid, recently confirmed via genetic testing to be a distinct species. This has taken five or six years to figure out that this is not the same species, says Brent Bean, agronomy director for the United Sorghum Checkoff Program. Bean says the two pests look essentially identical; however, they possess enough genetic differences and slight morpho-logical differences to separate the sorghum aphid, Melanaphis sorghi, from the sugarcane aphid, Melanaphis sacchari. David Kerns, Texas A&M University entomologist, says the most significant difference between the two pests is their host range and host preference. You can't tell the difference with the naked eye so the mainSorghum aphids can quickly reach threshold levels in susceptible thing to know is that if its in sorghum, its the sorghum aphid,sorghum varieties.PHOTO: BRENT BEANhe explains A true sugarcane aphid doesnt do well on sorghum, and vice versa.The sorghum producers took the big hit, Bean says. Aphids essentially destroyed the crop in years when infestations were Initial Efforts highest, and growers couldn't afford to make multiple insecti-While the enemy may have changed names, the battle continues. cide applications. That meant we really did need to have better Researchers detected the sorghum aphid in Texas in 2013.hybrids. Large populations led to significant crop losses and just twoThe industry came together and fortunately quickly discov-years later, the sorghum aphid was reportedly present in 17ered some existing sorghum lines with some level of resistance. states, as well as in Mexico.At that time, in a field where sorghum was susceptible, the Texas A&M AgriLife Extension research in the 2015 Journal ofentire crop was devastated with basically no grain yield, so the Agricultural and Applied Economics estimated the mean eco- fields that had resistance were obvious because while aphids nomic loss from sorghum aphid was just over $64 per acre. were present, the plants were still alive and had yield, Hayes says.When aphids hit the sorghum industry, it was really a signifi- Agronomists, entomologists and breeders spent the next cant problem, decimating millions of acres, says Chad Hayes, aseveral years evaluating hundreds of sorghum hybrids and find-sorghum breeder with the Agricultural Research Service of theing the few that could resist, while also working to identify and U.S. Department of Agriculture. incorporate the source of that resistance into other hybrids.30/ SEEDWORLD.COMDECEMBER 2023"