Transmissibility of Broad bean wilt virus 1 by aphids: influence of virus accumulation in plants, virus genotype and aphid species

Broad bean wilt virus 1 (BBWV-1) is transmitted by several aphid species ina non-persistent manner. Transmission efficiency by vectors is a key factorfor understanding virus epidemiology and applying disease control measuresbased on limiting virus spread. We evaluated the transmission rates of twogenetically divergent BBWV-1 isolates (PV-132 from USA and Ben from Spain)infecting broad bean (Vicia faba L.) by isofemale lines of nine aphid speciesfrom eight different genera collected in Spain. Our analyses showed that:(a) the virus concentration in the source plant was a key factor in BBWV-1transmissibility; (b) The Spanish isolate Ben was transmitted more efficientlythan the American isolate PV-132 by most aphid species, but this was onlydue to the higher accumulation of Ben in plants, as both isolates had similartransmissibility after adjusting virus concentration and (c) The transmissionrate varied greatly between the different aphid species.