Location: Sugarcane Field StationTitle: The aphid Melanaphis sacchari and the weed Sorghum almum – Partners in crime Author
Submitted to: Sugar Journal
Publication Type: Abstract Only
Publication Acceptance Date: 4/17/2016
Publication Date: 6/1/2016
Citation: Rott, P., Wei, C., Kaye, C., Hincapie, M., Mollov, D.S., Comstock, J.C., Nuessly, G. 2016. The aphid Melanaphis sacchari and the weed Sorghum almum – Partners in crime . Sugar Journal. 16JUN. Interpretive Summary: N/A
Technical Abstract: Sugarcane yellow leaf virus (SCYLV), the causal agent of yellow leaf disease of sugarcane, is widespread in Florida and vectored by the aphid Melanaphis sacchari. Sugarcane was the only known natural host of SCYLV in the USA until 2015 when a new natural host was found for this virus in Florida: Sorghum almum also known as Columbus grass. This grass is considered to be a noxious weed in several states of the USA and it is a common grass in proximity of sugarcane fields in Florida. Columbus grass was found infected by SCYLV in several locations including Canal Point, Belle Glade, and Clewiston. Since 2014 and the recent emergence of a new biotype of M. sacchari on grain sorghum in the Southern USA, S. almum was also found highly infested by this aphid species in Florida. In 2015, M. sacchari invaded grain sorghum (S. bicolor) plants newly grown in experimental trials at Belle Glade. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) assays and sequencing confirmed the presence of SCYLV in grain sorghum, Columbus grass, and sugarcane, as well as in M. sacchari individuals collected from these plant species. These data suggest that both S. almum (as an alternative host and reservoir of the virus) and M. sacchari (as the vector of the virus) are both involved in sugarcane yellow leaf. It may also explain why control of SCYLV using healthy virus-free seed-cane is only partially successful in Florida. Transmission of the virus from Columbus grass to sugarcane needs to be verified to investigate the importance of this potential secondary host of SCYLV in the epidemiology and control of sugarcane yellow leaf. Finally, occurrence of SCYLV in another cultivated plant besides sugarcane (i.e. grain sorghum) may be evidence for emergence of a new disease caused by SCYLV in the USA.