Aphid Alert 2024 - Monitoring PVY Vectors in Minnesota and North Dakota

Friday, August 5, 2022

Trap Catches to Aug 05, 2022.

Aphid vector numbers continued to rise this week, putting us into a later growing population than last year. By this time in 2021, aphid captures had already peaked and were decreasing while this year's populations are still growing (see graphs below). Last year's level of both aphid capture and PVY Vector Risk at this time of the season were much higher, mostly because of the number of English Grain Aphids which were numerous at all trapping locations in 2021. The temperatures drought of 2021 drove aphid numbers high early in the summer. This year, more moderate temperatures and more frequent rain have both moderated aphid population dynamics while providing better late season conditions for aphid populations in the area.

(Click on image for larger version)

The species composition of the aphid captures are different this year, with no individual species dominating the catch to the extent that English Grain Aphid did last year. That being said, Thistle Aphid was common this week and has become the most numerous vector captured this year and the only one to be recovered at all trapping locations. Soybean Aphids are starting to increase and are being recovered from more trap locations. This is not surprising for this time of year, Bruce Potter in Lamberton reported today that the southern migration has started this week. We can probably expect more Soybean Aphids in our traps next week. Cereal aphid numbers continue to rise, with the later maturing grain crop this year, these species also may well increase next week. We also recovered our first Green Peach Aphid since 2020 this week. Green Peach Aphid is, of course, the most effective vector of PVY. Only a single Green Peach Aphid was recovered, lets hope she's lonely!

So... Keep scouting, and we'll keep counting...

Click on any image below for full-scale version.

Cumulative PVY Vector Risk Index to Aug. 05, 2022