Seasonal Dynamics of Aphid Flights and Cotton Leafroll Dwarf Virus Spread in Alabama

Cotton leafroll dwarf virus (CLRDV) is an introduced Polerovirus (Family: Solemoviridae) of cotton, L., in the U.S. The only vector known to transmit this virus to cotton is the cotton aphid, Glover; however, there are seven other species of aphids (Hemiptera: ) reported to colonize cotton in the southeastern U.S.: (Thomas), (Sasaki), Koch, Thomas, (Sulzer), Westwood, and Scopoli. Little to no information is available on annual population dynamics of these species in the southeastern U.S. The timing of CLRDV spread to cotton plantings is also unknown. The objective of this study was to monitor the population dynamics of eight cotton-feeding aphid species concurrent with the spread of CLRDV at three different locations in Alabama. Aphids were monitored weekly for two years with yellow pan traps, and sentinel plants were deployed weekly to monitor CLRDV spread throughout the cotton-growing season. During the two years, most CLRDV spread at all locations occurred when was actively dispersing in the field. Early season spread at sites in south and central Alabama, when was not abundant, suggests additional aphid vectors are possible.