The Feeding Sites in Songhus Olerageus of Hyperomyzus Lagtugae, the Aphid Vector of Lettuce Necrotic Yellows Virus

Abstract

The feeding sites of the aphid H. lactucae on S. oleraceu8, the natural wild plant host oflettuce necrotic yellows virus, have been investigated. Of 159 identifiable terminal feeding sites seen in transverse sections of S. oleraceu8 stem, 92� 5% ended in the phloem and most of these were in the relatively young cells, 6� 9 % terminated in parenchyma cells, and 0�6 % in xylem. The high proportion of sites in the phloem indicates that lettuce necrotic yellows virus is probably acquired from that tissue.