A new aphid pest of sorghum has rapidly spread throughout north Florida this summer. Last year the white sugarcane aphid was reported causing damage in Texas, Louisiana, and in the western part of Mississippi. It has now moved eastward into Alabama, north Florida, and Georgia. The aphid was first identified in Santa Rosa County on July 29 after being alerted that it was causing damage to sorghum in Escambia County, Alabama.
This is apparently a new aphid biotype, that is different from the one that has been on sugarcane in south Florida for many years. This biotype of the insect appears to have changed its host from sugarcane to plants in the genus sorghum which includes grain sorghum, forage sorghums, sorghum x sudan crosses, and johnsongrass.
There are several aphids that feed on sorghum, but this one looks different and causes more damage. According to Dr. Kathy Flanders, Auburn Extension Entomologist, “the white sugarcane aphid is a light colored aphid with no obvious markings except for black tailpipes and black feet. Other aphids on sorghum have spots, a green stripe down the back, or have a black head, black legs and black tailpipes.”
White sugarcane aphid (WSCA) infestations can increase rapidly and cause severe crop damage and yield loss. This aphid is difficult to control with current insecticides labeled in Florida. Pyrethroid insecticides have been shown to make populations explode by killing their natural enemies. The only products labeled in Florida that have shown some level of control are Lorsban and dimethoate. However, in many cases these products have only reduced the aphids by 50%.
Recommended rates for Lorsban are 1-2 pints per acre. The preharvest interval (PHI) is 30 days for the 1 pint rate and 60 days for the pint rate. For dimethoate, the rate is 1 pint per acre with a 28 day PHI. Some states, such as Mississippi and Georgia, have been able to obtain a Section 18 Emergency Use Exception for Transform insecticide. Florida does not have a Section 18 label for Transform at this time.