Assessment of Consensus-Based Scouting for Management of Sugarcane Aphid (Heteroptera: Aphididae) in Georgia

The sugarcane aphid, Melanaphis sacchari (Zehntner) (Heteroptera: Aphididae), was recently recognized as a pest of grain sorghum, Sorghum bicolor (L.) Moench, in the southeastern United States. The objectives of the study reported herein were to evaluate the suitability of using a consensus-based scouting network and determine the timing of insecticide applications for management of sugarcane aphid in grain sorghum. The timing of insecticide applications was (1) application at 25 aphids per leaf, (2) application at 50 aphids per leaf, (3) a delayed application 1 week after occurrence of 50 aphids per leaf, or (4) not treated. Results showed that a single application of flupyradifurone at 15.4 g(AI)/ha consistently reduced populations to nearly zero for the remainder of the season, while aphid populations in the nontreated plots reached a peak of 300-400 aphids per leaf. Aphid populations on the upper leaves reached 50 aphids per leaf in nontreated plots 1 week after reaching the treatment threshold on the lower leaves. All plots receiving insecticide applications had similar estimated yields, which were >5 times greater than yields in nontreated plots. Results from the consensus-based scouting network showed that first detections and reported first commercial applications generally occurred within 1 week (range of 3-11 d) of the actual populations quantified in the research trials. These data suggest that initiating scouting for sugarcane aphid populations following notification of activity in the area through consensus reporting would provide adequate warning for preventing economic losses to sugarcane aphid.