09 Jul Agronomy Update – July 9th

Hi everyone,

Rain is in the forecast for tomorrow…hopefully we get that 10-15 mm.  There are quite a few areas of the province that could use that much or more in the near future. I have seen a couple irrigation pivots started by mid-week.

Christine ran the numbers on June rainfall:

Table 1: Rainfall amounts for the month of June (current year 2026 vs historical records 1981-2010)

As you can see, West Prince had a surplus of rain in June…I know a few communities that easily surpassed 135 mm.  The western and eastern ends of the province have had a surplus of rain so far this season, while the middle of the province is at about average overall.

Interesting, growing degree day totals are below average in the eastern half of the Island, while they are 10-15% above average in Prince County, up to June 30^th.

Crop Update Review:

Highlights from the Crop Update meeting held Tuesday afternoon by Zoom:

• Late blight spores have been detected at multiple locations in Maine at the first of this week.  No reports of foliar disease have made it to me yet. No late blight spore have so far been detected in New Brunswick.
• One grower reported finding grey mold (Bortrytis) symptoms in East Prince. Usually this is more of a late season disease, but cool, damp weather in June may have increased incidence. Chlorothanonil (Bravo/Echo) is the most cost-effective option for controlling grey mold, particularly if the incidence is light.
• CPB adults are being found across the province, worse in some areas than others. Egg masses and first instar larvae have also been observed.  According to the weekly pest prediction model published by the PEI Dept of Ag, We should hit the first larval peak in the next 4-5 days in most of the province (not Eastern Kings).
• Recommendation: do not use the same chemistry back-to-back to control CPB.  Alternate chemical groups to prevent resistance and maximize control.  Also, consider coordinating CPB sprays with your neighboring farms. If you all use the same product on the first spray and the same product on the second spray, that should also help with slowing resistance.
• European corn borer (ECB) moths have been trapped in potato and corn fields. Egg masses have been found in both West Prince and East Prince, laid late last week. We should be reaching 70% adult moth emergence by mid-week next week in West and Central PEI. NB is also reporting an above average ECB population this year.
• The timing for ECB spray is crucial, at blackhead stage on the egg masses (just ahead of hatching). Before or after this stage will have significantly reduced efficacy.

Spore Trapping Results:

 This is the first week of spore trapping results from Air Spore.  Not all locations have started, particularly in the eastern half of the Island.  Here are the averages from West Prince (west of Portage) and East Prince:

 These averages are from Monday and Wednesday of this week (July 6/8). It appears like we might be seeing an early peak of early blight spores in East Prince but not in West Prince.  This makes sense, as in general, more growers were able to plant earlier in East Prince than West Prince due to weather conditions. Growers are encouraged to get fungicides effective for both early blight and brown spot on before row closure, particularly in sensitive varieties. With a number of early-planted fields approaching row closure right now, timing is important!

Aphid Alert:

Aphid numbers remain very high across most of the province, increasing so far this week from last week. Green Peach aphid numbers are low but present early in the season.  Consistent oil and aphicide applications are recommended during this rapid growth stage.

Resources:

• AgIntel Weather Dashboard:  PEI Ag-Watershed/EPAA weather stations across the province.  Real-time weather data.  Note: this is a work-in-progress, with more options/tools coming and more stations to come online.
• PEI Dept of Ag Weather Stations:
• PEI Dept of Ag Pest Monitoring Network:  reports on insect pest trapping, degree day models, and aphid alert counts

AgriScout PVY Detection App:

Thank you to the large number of participants that we had for the Potato Roguing Clinic held on Tuesday.  Thanks to Rebecca MacSwain for organizing the event, Mary Kay Sonier for leading the workshop, and the farm staff at AAFC Harrington for hosting us for the in-field portion of the morning.

For those interested in trying UPEI’s PVY detection app, you can visit app.agriscout.ai for a QR code to scan with your phone, in order to download the app to your phone.

The AgriScout app is a work in progress, and so far only has a small number of varieties with full service.  However, please feel free to experiment with the app to try and identify PVY symptoms, and feel free to provide feedback on how the app works for you!

Next Week:

I will be travelling most of next week, first to the Annapolis Valley for the Institute of Agrologists and Atlantic OFCAF Ag Extension Conferences, then to Ontario on Friday for a quick trip.  If you have questions or concerns next week, please feel free to text or email me and I’ll get back to you as soon as I can.  I will send out an Agronomy Update on Thursday with up-to-date information.

Hopeful for some rain tomorrow!  Have a great weekend.

Ryan