Subterranean clover red leaf virus and other legume viruses in Canterbury

Abstract

Abstract To determine their importance as virus vectors, 1419 alate aphids were collected, mainly from field plots of garden peas ( Pisum sativum L. var. sativum L.) in spring 1966, 1967, and 1968; 55% were Aulacorthum solani (Kltb.), 25% Myzus persicae (Sulz.), 16% Macrosiphum euphorbiae (Thos.), and 3% Aphis craccivora Koch. Alatae of each species were transferred either singly or in groups to subterranean clover ( Trifolium subterraneum cv. Bacchus Marsh) test plants. The viruses detected and their vectors were: Subterranean clover red leaf virus (SCRLV), which caused the leaves of the test plant to be small and turn red as they matured. Alatae of A. solani often infected plants with SCRLV, and alatae of M. euphorbiae did so occasionally. In glasshouse tests SCRLV was transmitted circulatively by apterae of A. solani but not by apterae of M. persicae or A. craccivora , although M. persicae appeared to transmit SCRLV when PELRV was also present. Pea leaf roll virus (PELRV), which caused marked stunting of plants. Only some alatae of M. persicae infected the test plants. PELRV was transmitted circulatively by M. persicae but not by A. craccivora . Bean yellow mosaic virus (BYMV), which caused mosaic symptoms in test plants; only a few alatae of M. euphorbiae were viruliferous. Glasshouse tests on field samples of pea plants with top‐yellowing symptoms showed that these plants were infected more often with SCRLV than with PELRV. SCRLV was isolated also from field samples of lucerne, soyabean, and broad bean plants.