Comparison of Yellow Holocyclic and Green Anholocyclic Strains of Myzus persicae (Sulzer): Transmission of Beet Western Yellows Virus1

Abstract

In the Yakima Valley of Washington there are two distinct strains of the green peach aphid (GPA), Myzus persicae (Sulzer): a holocyclic yellow morph and an anholocyclic green morph. These two distinct color morphs were maintained for over 20 generations in the greenhouse on a number of different host plants. In tests with non-viruliferous GPA feeding on diseased sugarbeet, Beta vulgaris (L.), or hoary cress, Cardaria draba (L.) Desv., the holocyclic strain was slightly more successful in transmitting beet western yellows virus (BWYV) to an indicator plant, shepherdspurse, Capsella-bursa pastoris (L.) Medic., than the anholocyclic strain. However, viruliferous GPA of the holocyclic strain was less successful in transmitting BWYV to indicator plants after first feeding on noninfested sugarbeet or hoary cress plants (83 and 66% efficiency, respectively), whereas the anholocyclic strain was able to transmit BWYV at lesser rates (98 and 96%, respectively). These differences may have arisen because of selective factors resulting from the different winter hosts normally associated with the two populations.