Trap Catches to August 14, 2026.

Aphid numbers continue to rise this week. The total number of vector species of aphids captured across all locations jumped to 983 from last week's 602. This partially reflects a higher number of reporting traps this week, but average trap counts were up as well (54.6/trap compared to 33.84/trap last week). The average PVY Vector Risk Index rose this week from 4.6/location to 7.4/location; the increase in PVY Vector Risk Index at individual locations was highly variable. However, our regional aphid numbers and PVY Vector Risk Index values are well ahead of where they were last year.

In addition, we recovered our first Green Peach Aphids (GPA) for the season from 4 locations: three locations located in NW MN / NE ND and 1 in central MN. At this time GPA numbers are low, but they can and do increase rapidly in fields.  Green peach aphids are a colonizing species, so scouting both seed and commercial fields are highly recommended. 

Soybean captures rose again with double digit captures occurring at most locations. Cereal aphids (bird cherry-oat, corn leaf and English grain aphids) all remain numerous at many locations. Most other vector species also increased in number this week. The largest total capture numbers, and PVY Vector Risk Index values are now occurring in NW MN/NE ND.

Bottom line is our numbers are continuing to increase and vector species are well distrbuted across our trapping area. If vine kill has not occurred, the application of appropriate management should continue. 

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 8/14/2026

For Comparison, Cumulative PVY Risk Index by Site to 8/15/2025 

Aphid Species Capture and PVY Vector Risk Index for the week ending 8/14/2026

Cumulative Aphid Species Capture and PVY Vector Risk Index to 8/14/2026