Trap Catches to August 28, 2026.

Aphid numbers had a significant drop this week, dropping to nearly half of last week's. The average regional aphid capture/trap this week was ~48.8 aphids/trap compared to ~91.6 aphids/trap last week. The average PVY Vector Risk also dropped from 10.8/location to 6.8/location. Much of the decrease in vector catch was a significant decrease in the number of Soybean aphids recovered; last week there was an average of ~61 soybean aphids/trap, this week that was down to ~35/trap. 

One species that did increase this week was green peach aphid, average trap captures rose from ~1/trap last week to ~4 this week.  English grain aphid numbers rose, as did thistle, buckthorn and cotton/melon aphids. 

While regional aphid numbers have dropped this week, vector populations are still much higher than they were at this point last year and much higher than the 12 year average. There are still high populations of vector species flying. Many fields are being, or have already been vine killed. But remaining seed fields should still be protected.

Lets hope this drop signals the seasonal decrease generally recorded at the end of August. In any case, keep scouting and managing remaining seed fields. In addition, the numbers also remain threatening to processing and table potato fields. So keep on scouting!

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 assessment sites (like this one) and check weather-based predictive 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 8/28/2026

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