Transmission of Lettuce Mosaic Virus by a New Vector, Pemphigus bursarius

Abstract

Laboratory studies with the lettuce root aphid, Pemphigus bursarius (L.), and lettuce mosaic virus showed that three forms of the aphid tested were able to transmit the virus. P. bursarius was less efficient in transmitting the virus than Myzus persicae (Sulzer). The apterous root forms of P. bursarius transmitted the virus with less efficiency from foliage to foliage than they did from root to root. Sap inoculation tests using a local lesion host, Gomphrena globosa L., as an indicator, showed that less virus was present in the roots of lettuce mosaic virus infected plants than in the foliage. Transmission efficiency by the apterous viviparae did not significantly increase following a pre-access fast, but the aphids transmitted after a shorter access time. The fundatrigeniae of P. bursarius from poplar and the alienicolae from lettuce were also rather inefficient vectors of lettuce mosaic virus. However, the fundatrigeniae were superior vectors when compared with the alienicolae. A comparison of incubation periods of the virus in the plants when the virus was transmitted from foliage to foliage and from root to root showed mean incubation periods of about 7 days with foliage to foliage transmission and 15.5 days with root to root transmission.