Trap Catches July 11, 2025.
The number of aphid species capture in the traps doubled over last week, with a much greater percentage being vector species. With 19 traps reporting, traps recovered a total of 126 aphids, of which 53 were vectors. This tracks well with the 13 year average; at this point in the growing year, some alternate hosts are maturing and becoming less suitable hosts, resulting in the development of winged aphids dispersing to establish new colonies on better food sources. If we stay true to the average pattern, we can expect vector numbers to start increasing sharply (see the graph below demonstrating the average regional capture from 2013-2024).
The traps captured a number of different vector species, however, cotton-melon aphids were widespread, both buckthorn and potato aphids were present in several sites, and we started to see the appearance of Damson-Hop aphids at multiple sites this week. Green peach aphids remained low, with only a single individual being recovered at one location.
Keep scouting and checking predictive sites!
The usual reminder:
- keep 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 can't survive on potatoes, consequently they'll keep moving through the field, sampling additional plants and spreading inoculum in the field. Remember to check predictive sites like this one and University of Wisconsin's weather based Vegetable Disease & Insect Forecasting site,(https://agweather.cals.wisc.edu/vdifn) which uses current weather data and historical populations as a predictor of current aphid vector populations. These will give you a better idea of the potential presence of non-colonizing aphids.
- 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 usually not effective enough at suppressing PVY transmission, but are still very useful parts of your management program. Treating fields with one of the anti-feeding insecticides (e.g. Sivanto Prime, Sefina, Transform, Fulfill or Beleaf) to control colonizing aphids, such as green peach, potato, or cotton melon aphids, can be beneficial in decreasing movement of PVY inoculum within fields
- aphids preferentially first colonize fields at the edge. Using border crops in the headlands may decrease aphid colonization. But 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 those border crops when treating the field for colonizing aphids.
Happy scouting and have a great weekend!
Click on any image below for full-scale version.
Cumulative PVY Risk Index by Site to 7/11/2025
Cumulative PVY Vector Risk Index by Site to 7/12/2024 for Comparison
Aphid Species Capture and PVY Vector Risk Index for the week ending 7/11/2025
Cumulative Aphid Species Capture and PVY Vector Risk Index to 7/11/2025
