Attributes of Bean Yellow Mosaic Potyvirus Transmission from Clover to Snap Beans by Four Species of Aphids (Homoptera: Aphididae)

Abstract

After characterization of the natural spread of necrosis-inducing Bean yellow mosaic potyvirus (family Potyviridae, genus Potyvirus, BYMV(N)), nonpersistently transmitted from clover, Trifolium repens L., to an adjacent field of snap bean, Phaseolus vulgaris L., in western Oregon, we established a study site enabling us to investigate the virus reservoir, to observe en masse transmission of BYMV(N) to bean plants, and to identify aphid species associated with virus spread. Colonies of Myzus persicae (Sulzer), Acyrthosiphon pisum (Harris), and Aphis fabae Scopoli associated with virus spread were established in an insectary and shown to vector this virus. Although Nearctaphis bakeri (Cowen) comprised 68% of aphid alatae taken from bean leaves during virus spread, we were unable to show that this species could vector the virus by using the same methods that were successful for the other species. Instead, we found that when two distinct N. bakeri colonies unexpectedly emerged from the roots of T. repens BYMV(N) source plants (WZwc #6 and #11) that were present in the laboratory (insectary), these aphids transmitted BYMVN at rates comparable with those of M. persicae and A. pisum. Transmission of BYMVN also occurred with two other N. bakeri colonies maintained for 4 mo on Trifolium pratense L. (NZwc Sch 3B and Sch 7C) BYMVN source plants. Each of these four BYMVN transmission successes also demonstrated an unprecedented once-only transmission of BYMV(N) by N. bakeri colonies. Our experience with western Oregon N. bakeri colonies was compared with descriptions of this native North American species after its 1960-1980s arrival in France, Germany, and Italy.

Pea Aphid as both Host and Vector for the Phytopathogenic Bacterium Pseudomonas syringae

“…As it traverses the plant surface, the aphid continually evaluates the suitability of the host, with some aphid species sampling plant fluids with droplets of saliva that are expelled and reingested (3). This saliva can contact the plant surface where many bacterial epiphytes reside, such as the ubiquitous phytopathogens Pantoea agglomerans and Pseudomonas syringae (4,5,10,21,22,32).The pea aphid, Acyrthosiphon pisum, feeds on a variety of agriculturally relevant crop plants in the Fabaceae, including soybean (Glycine max), fava/broad bean (Vicia faba), pea (Pisum sativum), and snap bean (Phaseolus vulgaris) (15,28,(34)(35)(36), and has been shown to vector bean yellow mosaic virus between these hosts (15,(34)(35)(36). Several of these plants are also primary hosts for the highly aggressive bean pathogen Pseudomonas syringae pv.…”

“…The pea aphid, Acyrthosiphon pisum, feeds on a variety of agriculturally relevant crop plants in the Fabaceae, including soybean (Glycine max), fava/broad bean (Vicia faba), pea (Pisum sativum), and snap bean (Phaseolus vulgaris) (15,28,(34)(35)(36), and has been shown to vector bean yellow mosaic virus between these hosts (15,(34)(35)(36). Several of these plants are also primary hosts for the highly aggressive bean pathogen Pseudomonas syringae pv.…”