|PAUDYAL, SULOCHANA - Oklahoma State University|
|Armstrong, John - Scott|
|GILES, KRISTOPHER - Oklahoma State University|
|ROTT, PHILIPPE - University Of Florida|
|PAYTON, MARK - Oklahoma State University|
Submitted to: Trends in Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/27/2019
Publication Date: 10/19/2019
Citation: Paudyal, S., Armstrong, J.S., Harris-Shultz, K.R., Wang, H., Giles, K.L., Rott, P.C., Payton, M.E. 2019. Evidence of host plant specialization among the U.S. sugarcane aphid (Hemiptera: Aphididae) genotypes. Trends in Entomology. 15:47-58.
Interpretive Summary: We genotyped and phenotyped two unique sugarcane aphid biotypes, one collected from Florida sugarcane, and known as the "sugarcane type" and the other collected from grain sorghum in Texas and known as the "sorghum type". The two biotypes could not be separated taxonomically or morphologically. We now know there are two biotypes of the sugarcane aphid within the United States.
Technical Abstract: The sugarcane aphid (Melanaphis sacchari (Zehnter) (Hemiptera: Aphididae) has become a serious pest in the United States and the number one rated pest of sorghum (Sorghum bicolor (L.) Moench) since it was detected in Texas in 2013. The sugarcane aphid was considered only a pest on sugarcane in Florida and Louisiana for over three decades before the 2013 outbreak. Recent studies suggest that the 2013 outbreak in sorghum was because of the introduction of a new genotype. Our scope for this study was to quantify the phenotypic behaviors (host suitability as measured through life table statistics) and genetic diversity among sugarcane aphid clones collected from different hosts. We collected a diverse group of sugarcane aphid clones that colonized sorghum (SoSCA), sugarcane (SuSCA), and Columbus grass (CoSCA) and determined host suitability when introduced to five different hosts plants that included a resistant and susceptible grain sorghum, sugarcane, Columbus grass, and Johnsongrass. Sugarcane aphid clones from different hosts and geographical regions varied in performance among plant hosts. The survivorship and reproduction of the sugarcane collected aphid clone (SuSCA) was significantly higher when offered sugarcane (>85%) as compared to other hosts and in contrast, there was negligible survival and reproduction when SoSCA and CoSCA were offered sugarcane as host. Genotyping of these three clones along with two other known control aphid collections with the microsatellite markers indicated that SuSCA was a different MLG (multilocus genotype) when compared to SoSCA and CoSCA, that were what we call a MLF type. Our results suggest that there are 2 different biotypes of the sugarcane aphid within the United States, and that they cannot be distinguished by taxonomic or morphometric characteristics.