Identification key for cotton-feeding aphids (Hemiptera: Aphididae) found in pan traps in the Southeast

The introduction of cotton leafroll dwarf virus (CLRDV) (Family: Solemoviridae, Genus: Polerovirus) into the southeastern U.S. Cotton Belt has prompted research into understanding the epidemiology, including identification of potential insect vectors. Aphids (Hemiptera: Aphididae) are vectors of cotton-infecting poleroviruses. Of the eight aphid species reported to feed on cotton in the U.S., only Aphis gossypii Glover has been reported to transmit the phloem-limited virus, CLRDV, to cotton. Population dynamics of alatae aphids and additional information regarding CLRDV spread throughout the year may help identify other vector species. Using insect traps to monitor populations of these aphids is more effective for the seven species that are seldom observed, or difficult to sample because they feed underground on roots. However, current identification keys for aphids rely on using apterous colonies already infesting known host plants or are not specific to cotton fields. Here, we present a modified key for identifying cotton infesting aphids captured in pan traps around agricultural fields in the southeastern U.S., including A . gossypii, Protaphis middletonii Thomas, Aphis craccivora Koch, Rhopalosiphum rufiabdominale Sasaki , Macrosiphum euphorbiae Thomas , Myzus persicae Sulzer , Aphis fabae Scopoli, and Smythurodes betae Westwood. Pictures are provided to aid in the identification of these species.