Bean Yellow Mosaic Virus Transmission by Myzus Persicae

Abstract

Efficiency of bean yellow mosaic virus (BYMV) transmission from broad bean source plants varied with age of leaf on which aphids, Myzus persicae (Sulz.), fed. Duration of infection in the source plants did not affect transmission. Observations of acquisition feeding behaviour yielded results which are interpreted to indicate that most transmission occurs with virus acquired intracellularly. Aphids from thriving M. persicae colonies on young leaves of Brassica pekinensis Rupr. transmitted BYMV to more plants than did a comparable group of aphids from mature leaves. Likewise, aphids from thriving colonies on young leaves transmitted the virus to more plants than did aphids from older colonies on heavily infested, deteriorating plants. These differences in transmission were not explained by comparable transmission tests with adult apterae and fourth instar alatiform nymphs nor by the feeding behaviour of aphids on healthy test plants. No differences in transmission were found between apterous adults and fourth instar alatiform nymphs. The number of plants infected in successive replicates by aphids from uniform colonies was more consistent than that by aphids from variable colonies. Transmission increased with increasing duration of probes on healthy test plants. The number of probes was not as important as total probing time. Non-feeding M. persicae gradually lost the capacity to transmit BYMV following the acquisition feeding. Virus was retained for at least 4 hr.