Aphid transmission of broad bean wilt virus and comparative transmission efficiency of three vector species

Abstract

Broad bean wilt virus has been transmitted experimentally by the green peach aphid, Myzus persicae (Sulz.), by using short feed techniques as applied to non-persistent viruses. A comparative study of transmission was made between this aphid and the aphids Aphis craccivora Koch and Macrosiphum euphorbiae (Thos.). After short (10–15 sec), naturally terminated access probes on low concentration virus source plants, and successive single probe transfers, starved pairs of M. persicae aphids infected 27 of 110 plants inoculated in two experiments, whereas A. craccivora failed to infect any test plants. In comparisons between individual starved aphids given single access and transmission probes on high concentration virus source plants, the infection rate for M. persicae approximately trebled those of A. craccivora and M. euphorbiae. Differences in transmission ability were generally more pronounced when aphids probed low concentration virus source plants. Groups of 10 M. persicae were able to transmit after a 24 hr access to a high concentration virus source plant, but less efficiently than after single access probes on the same plant. The virus was not retained by the aphid after an additional 24 hr period on healthy broad beans. A. craccivora failed to transmit after a 24 hr exposure to the same source. The experimental results provide an explanation of the manner of field spread of the virus, and of the control obtained by regulation of sowing time. They also demonstrate that broad bean wilt is a typical non-persistent virus, apparently unrelated to other viruses which infect broad bean.