Insect Strip

Insect Strip

Friday, May 23, 2014

Update on the Sugarcane Aphid

On the Lookout for the New Sorghum Aphid

Most people have heard about the fall, 2014 sugarcane aphid (Melanaphis sacchari) outbreak in the Lower Rio Grande Valley, Gulf Coast counties and Louisiana, Mississippi and Oklahoma. The USDA Agricultural Research Service and others have conducted genetic tests and determined that the new pest is in fact the sugarcane aphid but it has switched hosts to sorghum for some unknown reason. It is still being found on sugarcane in the affected counties, but the majority of the insects are on sorghum. Our colleagues downstate are now reporting treatable levels of sugarcane aphids in some fields, and they are also reporting an increasing number of winged adults. It is a long distance from the infested fields downstate to the Texas High Plains, but these winged aphids can easily ride wind currents and storm fronts. So there is a slight risk that aphids will reach the High Plains. We have no idea if this semi-tropical species can survive and reproduce in our climate, but it is worth watching for them in our sorghum and other sorghum related plants.

Distribution of white sugarcane aphid in 2013
There has been a bit of confusion about the name of the new pest. Sugarcane aphid and yellow sugarcane aphid sound a lot alike. In order to avoid potential confusion, Texas and Louisiana entomologists have agreed to bend the rules and will now use the name “white sugarcane aphid” when talking about Melanaphis sacchari, the new pest on sorghum. 

We know that this aphid can be found on sorghum, forage sorghums, sorghum x sudan crosses, johnsongrass, sugarcane and occasionally on corn. We do not think there is a significant threat to corn, in part because the aphids now on corn in the Lower Rio Grande Valley do not seem to be in healthy colonies; sorghum and its relatives seem to be far better hosts. Early detection will give us a chance to monitor this aphid and perhaps learn a lot about it, and it will also let us get a jump on some insecticide trials so that we can look for new products. We would appreciate receiving reports of white sugarcane aphid or any unusual aphid problems in sorghum. 

Identification of the white sugarcane aphid

The three common aphid species we find on High Plains sorghum are the greenbug, corn leaf aphid and the yellow sugarcane aphid (Sipha flava). The following photos illustrate the recognition and identification characteristics of white sugarcane aphid and each of our common species.

This post was prepared by Pat Porter (Lubbock), (806) 746-4046 and Ed Bynum (Amarillo), (806) 677-5600. Photo credits: White sugarcane aphid by Scott Armstrong, USDA-ARS; Yellow sugarcane aphid, Greenbug, and Corn leaf aphid by Rick Grantham, Oklahoma State University.