Tillman, Devin Marie (2016-05). The Study of Melanaphis sacchari (Hemiptera: Aphididae) (Zehtner) (Sugarcane Aphid) and Sorghum bicolor (Cyperales: Poaceae) (L.) Moench (Sorghum) Interactions. Master's Thesis.
Sorghum bicolor (L.) Moench (Cyperales: Poacea) is a cereal grain crop grown worldwide. National Agriculture Statistics Service reported that in 2014 and 2015 over 6 million hectares of sorghum were planted in the United States and the value of grain sorghum was over $1.6 billion. Sorghum is an important staple crop for many countries and is used as mainly fodder for livestock. Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), the sugarcane aphid, is a new invasive pest of sorghum in southern U.S. It was first observed in sorghum in 2013 in Texas, but high infestations caused important losses in 2014 in several southern states (Louisiana, Mississippi, and Oklahoma). The novelty and the speed of invasion of this pest caught the industry by surprise, and today few control options are available. In order to develop sustainable control strategies a life table analysis was first conducted of the sugarcane aphid on five sorghum hybrids. These included both grain, sweet and photoperiod sensitive sorghum hybrids. Only the sugarcane aphid overall survivorship was significantly different between hybrids ATx645/R07007 (grain sorghum) and A0535-C53-6F/UMBRELLA (sweet sorghum). Genetic resistance was then evaluated to sugarcane aphid in 16 commercial grain sorghum hybrids in Burleson County, TX on the Texas A&M University farm. No resistant hybrid to sugarcane aphid was determined because the aphid population was below the threshold that would affect sorghum yield. Finally sorghum defenses against sugarcane aphid were evaluated through a transcriptome analysis post insect feeding. Plants recognized aphid attack, mounted defenses, but those responses were insufficient in deterring feeding.