Jane Pierce, agronomic entomologist at New Mexico State University, is warning growers of the possibility of finding sugarcane aphid moving into New Mexico.
“Sugarcane aphid is a new aphid pest of sorghum. This aphid either expanded its diet from eating sugarcane to sorghum or came in as a new biotype,” Pierce said.
Over the last year the sugarcane aphid moved from south Texas to the Panhandle, and last year it was spotted northwest of Lubbock, near Plainview, Texas and Amarillo. It was also collected in Oldam County, Texas right on the border of New Mexico, and Pierce said could be in New Mexico right now.
“We will keep an eye out to see if we can spot the aphid in sorghum fields or on johnsongrass, a common weed. It will probably be found first around the Portales area. As soon as anyone spots the aphid NMDA can apply for permission to use the most effective insecticide,” Pierce said.
Sugarcane aphid looks similar to some other sorghum aphids, particularly yellow sugarcane aphid and greenbug. However it is easy to distinguish the three species. Unlike sugarcane aphid, yellow sugarcane aphid has numerous hairs on its back and the greenbug has a green stripe down its back.
“Populations of sugarcane aphid can be enormous. They reproduce rapidly and are moved by wind,” Pierce said. “Growers can see losses of 25-50 percent. Some fields have been so bad that growers have abandoned them. One of the big problems is when sticky secretions from the aphids clog harvesting equipment.”
Beneficial insects often help control insect pests in New Mexico, but growers cannot expect beneficials to keep up with this rapidly reproducing pest. “Dry desert conditions also help control many insect pests in New Mexico,” Pierce added. “We may see some dessication in grain sorghum however, in forage sorghum we have higher humidity in the canopy so we shouldn’t expect much help in that situation.”
Fortunately, if an insecticide is applied at the recommended economic threshold of 50-125 aphids per leaf, growers can generally see good control with just one application, Pierce explained.
Pierce urges growers to talk to their county agents and take any insects or damaged plants to them to be examined if they see unusual problems.