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

Trap Catches to July 31, 2026.

Aphid numbers took a huge jump in the past week. Aphid counts are up across the region with grain aphids leaving maturing wheat fields and soybean aphids starting their late July/early August dispersal flights. Regional PVY Vector Risk Index values have jumped with the populations and are now higher than at this point last year.  The increase occurred across the  trapping network with average captures per trap increasing at almost all locations reporting this week. This has resulted in an increase in average PVY Vector risk at all locations.   

We saw an increase in almost all vector species. The numbers of the 3 small grain aphid vectors most common to our area (bird-cherry oat, corn leaf and English grain aphids) increased at almost all trap locations. Other vector species such as cotton-melon and buckthorn aphids also saw a significant increase. Soybean aphids were by far the most numerous species at all locations, with some sites suffering very large flights this past week. Large soybean aphid flights are not unusual in MN and ND in late July and early August and are sometimes part of our late season PVY epidemiology. 

With much higher numbers of vectors present this week remember to scout and use appropriate management tactics.

 The usual reminders:

- vector flights have started, 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 7/31/2026

For Comparison, Cumulative PVY Risk Index by Site to 8/01/2025 

Aphid Species Capture and PVY Vector Risk Index for the week ending 7/31/2026

Cumulative Aphid Species Capture and PVY Vector Risk Index to 7/31/2026

  Trap Catches to July 24, 2026.

Aphid vector numbers remain behind those of last year as does the PY Vector Risk Index. Average capture per trap was similar to that of the previous week (1.7 vectors/trap vs 2.2 vectors/trap last week) but the total number of vectors captured across the region has increased slightly. This reflects aphids being captured at more locations, albeit still at low numbers. 

Soybean aphids remain relatively common, being collected at most locations. Small grain aphids are beginning to become more common and Buckthorn aphids remain steady.

Expect more small grain aphids as the season progresses. While the return of high temperatures during the day may decrease reproduction rates, our night temperatures will be within good reproduction temperatures.

While trap numbers are low, aphid vectors are flying. Use appropriate management tactics.

Keep on Scouting.

 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 7/24/2026

For Comparison, Cumulative PVY Risk Index by Site to 7/25/2025 

Aphid Species Capture and PVY Vector Risk Index for the week ending 7/24/2026

Cumulative Aphid Species Capture and PVY Vector Risk Index to 7/24/2026

 

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

  

Trap Catches to July 10, 2026.

More traps are starting to respond this week. We've had some technical difficulties, but we're sorting that out as we go. Apologies for this report being late, I've been out sick since last Thursday but am slowly on the mend. 

 The average number of vectors per trap doubled over last week (1.14/trap this week and ~0.5/trap last week) so the vector counts remain low. We are behind last year's populations at this date but we also have fewer traps responding so far. We'll get a better picture as more traps come online.

As far as species are concerned, English Grain and Soybean aphids were the most numerous species recovered. The average number of non-vector species also rose over the previous week. So we are staring to see the aphid populations build, pretty much on schedule... 

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.

Happy 4th and have a great upcoming week.

Click on any image below for full-scale version.

Cumulative PVY Risk Index by Site to 7/10/2026

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

Aphid Species Capture and PVY Vector Risk Index for the week ending 7/10/2026

Cumulative Aphid Species Capture and PVY Vector Risk Index to 7/10/2026

 

Trap Catches July 03, 2026.

Our trapping networks are starting to return samples and numbers of aphid vectors per location remain low at this stage. However, weather fronts passing through the region, increasing temperatures and growing canopies will likely result in higher numbers over the next several weeks.

Soybean aphids were recovered at a couple of locations. Although their vector efficiency (the measure of how successfully they transmit PVY virus when compared to Green Peach Aphid) is relatively low compared to many other species, their high populations and tendency to move in high numbers means they are a very important vector of PVY in the North Central plains.   

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.

Happy 4th and have a great upcoming week.

Click on any image below for full-scale version.

Cumulative PVY Risk Index by Site to 7/03/2026

For Comparison, Cumulative PVY Risk Index by Site to 7/03/2025 

Aphid Species Capture and PVY Vector Risk Index for the week ending 6/27/2025

Cumulative Aphid Species Capture and PVY Vector Risk Index to 7/03/2026

 

Trap Catches June 26, 2026.

It's been  a slow start to the aphid trapping season. It's been a slow start to the aphid trapping season. With 5 sites reporting since mid-June, aphid vectors have been recovered at 4 locations. Aphids have started flying and so it's time to start scouting. Vector species were limited but included soybean, cotton-melon, pea and cotton-melon aphids. There were a few non-vector species recovered, but aphid captures / trap remain low.  Still, vector species are flying, so start scouting and checking the trap and predictive data.

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.

Happy scouting and have a great upcoming week.

Click on any image below for full-scale version.

Aphid Species Capture and PVY Vector Risk Index for the week ending 6/27/2025