Effects of the pyrethroid deltamethrin on the acquisition and inoculation of viruses by <i>Myzus persicae</i>

Abstract

SUMMARY The pyrethroid, deltamethrin, alone or as an emulsifiable formulation, hindered infection of healthy plants with the persistent beet mild yellowing virus (BMYV) and both acquisition of, and infection with, the non‐persistent potato virus Y (PVY) and the semi‐persistent sugar beet yellows virus (BYV) by Myzus persicae in glasshouse tests. Another pyrethroid, RU‐15525, also protected against infection with PVY. Even sub‐lethal amounts of deltamethrin decreased virus transmission by rapidly incapacitating the aphids, the effect being least with aphids most resistant to organophosphorous insecticides and to certain pyrethroids including deltamethrin. Demeton‐S‐methyl hindered infection only with BMYV. This work shows that deltamethrin restricts transmission of persistent, semi‐persistent and perhaps more importantly of non‐persistent viruses in the glasshouse, and has potential for doing the same in the field.