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Vector Relations

A Non-Aphid-Transmissible Isolate of Bean Yellow Mosaic Virus-Scott That Is Transmissible from Mixed Infections with Pea Mosaic Virus-204-1. H. A. Hobbs, Postdoctoral research associate, U. S. Department of Agriculture, Agricultural Research Service, Crop Science Research Laboratory, Forage Research Unit, P.O. Box 5367, Mississippi State, MS 39762; M. R. McLaughlin, Research plant pathologist, U. S. Department of Agriculture, Agricultural Research Service, Crop Science Research Laboratory, Forage Research Unit, P.O. Box 5367, Mississippi State, MS 39762. Phytopathology 80:268-272. Accepted for publication 19 September 1989. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1990. DOI: 10.1094/Phyto-80-268.

An isolate of bean yellow mosaic virus (BYMV-Scott) that was not transmissible from single infections of pea (Pisum sativum 'Dwarf Gray Sugar') by Aphis craccivora was transmissible from mixed infections with pea mosaic virus (PMV-204-1). The relative transmission efficiency of BYMV-Scott compared with PMV-204-1 averaged 20% from mixed infections (8–14% transmission of BYMV-Scott versus 39–70% transmission of PMV-204-1). BYMV-Scott seldom was transmitted alone from mixed infections. Sequential probing by aphids on PMV-204-1-infected pea tissue, then on BYMV-Scott-infected pea tissue, resulted in transmission of PMV-204-1 only. Aphids probing sequentially on BYMV-Scott-infected pea tissue and then through membranes on purified virions of PMV-204-1 or clover yellow vein virus (CYVV-Pratt) transmitted PMV-204-1 and CYVV-Pratt to 35 and 45% of test plants, respectively, indicating that an active helper component was available in BYMV-Scott-infected pea. Aphids that sequentially probed on BYMV-Scott or PMV-204-1-infected pea tissue and then through membranes on purified BYMV-Scott transmitted BYMV-Scott at very low levels (2–7%). The specific infectivity of BYMV-Scott was lower than those of PMV-204-1 and CYVV-Pratt. Virion properties of this isolate of BYMV-Scott apparently are responsible for its lack of aphid transmissibility from single infections.