Abstract: Pea necrotic yellow dwarf virus (PNYDV), a nanovirus, was proven in 2010 for the first time in Austria. Hosts of this virus are mainly legumes and vectors are reported to be aphids. In 2016 PNYDV caused severe crop losses right up to complete failures in field beans and peas. Therefore the Austrian Agency for Health & Food Safety and the Austrian Chamber of Agriculture established a warning system for the aphid virus vectors of PNYDV. The black bean aphid (Aphis fabae) and the pea aphid (Acyrthosiphon pisum) are known as major virus vectors. In 2017 flight activity of aphids was examined in 9 different trial sites by observing them on their winter hosts in March and April and by using yellow water traps in April and May. Aphids were tested for PNYDV using PCR analysis. The first winged A. fabae were trapped at the end of April in Gleisdorf, Styria. A. pisum firstly occurred in the middle of May on peas in the Marchfeld, Lower Austria. Nevertheless an early PNYDV infection of legumes or infected aphids could not be detected this year. Infected aphids and legumes could be proven from the end of June on.