Trap Catches to July 17, 2026.

Aphid vector numbers continue to rise slowly but we remain far behind last year's populations. While the average number of vector species recovered from traps was up by 50% this week (2.2/trap this week vs 1.5/trap last week), the low numbers means that isn't yet a large increase. So vector aphid counts and the PVY Vector Risk Index remain relatively low. As a reminder, by July 18 last year, we had already recovered Green Peach Aphid from a number of locations and that species has not yet been collected this year. Soybean aphid numbers remain close to last year’s but we have yet to see a lot of movement from small grain aphids moving into potato fields. Potato and Pea aphids were both recovered from multiple locations, as were Buckthorn aphids.

Please keep in mind, this does not mean these low numbers will persist (yes, I know, I know... pest management is always doooom and gloooom!). Recent temperatures and weather conditions have not been optimal for aphid reproduction, which probably contributed to our low trap numbers. 

Aphid vectors are flying, temperatures across the region are edging back down which will facilitate higher rates of aphid reproduction, and there's certainly time left in the season.  Bottom line, keep scouting and using appropriate management tactics.   

The usual reminders:

- vector flights have started, so start scouting; aphids can establish early after potatoes are up. Field scouting is less effective at finding aphd 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.

Have a great week and keep on scouting!

Click on any image below for full-scale version.

Cumulative PVY Risk Index by Site to 7/17/2026

For Comparison, Cumulative PVY Risk Index by Site to 7/11/2025 

Aphid Species Capture and PVY Vector Risk Index for the week ending 7/17/2026

Cumulative Aphid Species Capture and PVY Vector Risk Index to 7/17/2026