Competency for Yellow Dwarf Virus Transmission in the Rose‐Grain Aphid, <i>Metopolophium dirhodum</i> , Is Driven by Virus Species Not Vector Genotype

ABSTRACT Yellow dwarf viruses (YDVs) are a group of aphid‐vectored viruses that affect cereal crops and cause yellow dwarf disease. There are three main YDV species of concern in Europe: barley yellow dwarf virus PAV (BYDV‐PAV), BYDV‐MAV and BYDV‐PAS. These YDV species can be vectored by several cereal aphid species, although information is lacking for the rose‐grain aphid ( Metopolophium dirhodum ), a vector species of significant concern during spring and summer. Several biological factors have been found to influence vectoring capacity in cereal aphids, including (i) the competency for each YDV species, (ii) genotypic diversity in vector populations and (iii) host plant species. However, the extent to which some of these factors influence the vectoring capacity of rose‐grain aphids has not yet been examined in detail. Here, we used multiple aphid and virus populations to examine how these factors influenced vector competency in the rose‐grain aphid. We found that virus species is the most important factor influencing YDV transmission, with minimal variation between aphid genotypes. Across all genotypes we observed high competence for BYDV‐MAV, moderate competency for BYDV‐PAV, and little competency for BYDV‐PAS. These results further our understanding of the role virus and vector diversity play in determining the disease risk in an understudied vector, generating insights that can support the development of more sustainable vector and virus management options.