Trap Catches to August 07, 2026.
Aphid numbers took another jump this past week. Average aphid captures per trap across the region were up by approximately 30% from last week. This year we're seeing more diversity of vector species than last year but we still haven't recovered green peach aphid at any location (although a possible population was reported from a field in central MN). Nevertheless, we are catching a wide variety of vector species that are effective vectors, and catching some less effective vectors in high enough numbers that they still made a significant contribution to the PVY Vector Risk Index values. We continue to eclipse the potential risk levels we saw at this time last year. And August is when we see our aphid captures increase until they peak in late August/early September.
Soybean aphid was, by far, the most numerous vector captured this week accounting for more than half of the total regional capture. It is widely distributed and was recovered at every reporting trap location. Several locations received large flights with one trap capturing more than 100 aphids. Even though soybean aphid is not a highly efficient vector, when we get flights like this, it becomes a numbers game. By sheer size of population, I suspect soybean aphid has become one of the most important vectors of virus diseases to potato in the region.
While almost every vector we monitor was represented somewhere in the trapping network this week, small grain aphids continued to increase, with all three species being well represented. Buckthorn and cotton/melon aphids were both numerous and well distributed and numerous species of non-vector species were recovered from several locations.
Bottom line, there are a lot of aphids flying out there right now. Some fields are going to be vine-killed shortly, some locations have already started. For those fields that are still growing, an entomologist out west working in a system with similar concerns about aphid-borne disease once said, 'if it's green, by an aphid it'll be seen'. In other words, continue appropriate management until vine kill...
The usual reminders:
- vector flights are getting heavy, so continue scouting; aphids can establish early after potatoes are up. Field scouting is less effective at finding aphid vector species that don't colonize potatoes. While these species will enter potato fields and probe plants, they cannot survive on potatoes. Consequently, they'll keep moving through the field, sampling more plants and potentially moving inoculum already in the field to uninfected plants. Consult risk assesment sites (like this one) and check weather-based predicitve models like University of Wisconsin's Vegetable Disease & Insect Forecasting site (https://agweather.cals.wisc.edu/vdifn).
- the research literature reports that the use of crop oils is the most consistent post-planting technique in preventing transmission of PVY and it can be improved with the addition of the insecticide Lambda-Cyhalothrin.
- most of the research indicates that insecticides on their own are not effective enough at suppressing PVY transmission, but are still useful parts of your management program. Treating fields with one of the anti-feeding insecticides such as Sivanto Prime, Sefina or Transform to control colonizing aphids, such as green peach, potato, or cotton melon aphids, can be beneficial
- if using a border crop, it's a good idea to use treated seed to prevent the development of potential vector species in that border and to include the border plants when applying foliar insecticides in the field.
Have a great week and keep on scouting!
Click on any image below for full-scale version.
Cumulative PVY Risk Index by Site to 8/07/2026
For Comparison, Cumulative PVY Risk Index by Site to 8/01/2025 
Aphid Species Capture and PVY Vector Risk Index for the week ending 8/07/2026
Cumulative Aphid Species Capture and PVY Vector Risk Index to 8/07/2026
