Biology and management of the sugarcane aphid, Melanaphis sacchari (Zehntner), a new pest of sorghum, Sorghum bicolor (L.), in Alabama

Abstract

The sugarcane aphid, Melanaphis sacchari (Zehntner), emerged as a new pest of sorghum in Texas and Louisiana in 2013, and has since spread rapidly throughout the Southern United States. Management of sugarcane aphid is difficult due to its rapid reproductive rate, our lack of knowledge on the biology and ecology of this emerging pest, and limited data on management options. The overall objective of this research was to develop an integrated pest management program for sugarcane aphid. Small plot research trials were conducted at several locations throughout Alabama to: 1) evaluate the efficacy of foliar and seed applied insecticides, 2) assess commercially available sorghum varieties for resistance and/or tolerance to sugarcane aphid, and 3) determine the most effective combination of these tactics for sugarcane aphid management in Alabama. The addition of all seed treatments including Cruiser® 5FS, Gaucho® 600, NipsIt® Inside, and Poncho® 600 managed populations below treatment threshold for at least 47 days after planting. Foliar insecticides showed that both rates of Sivanto® 200SL maintained populations below treatment threshold for 27 and 34 days after treatment, while Centric® 40WG and both rates of Transform® WG provided efficacy for 20 days after treatment. Several sorghum varieties including DeKalb 37-07, DowAg 1G588, DowAg 1G851, and Pioneer 83P17 showed high levels of tolerance to sugarcane aphid, however these results varied upon location. The most effective treatment combinations tested that produced the highest yields were early-planted and used Pioneer 83P17 with or without the addition of seed treatments. All early-planted treatments required one insecticide application, while only one of the late-planted treatments required one, however all late-planted treatments produced lower yields than early-planted treatments.