Agronomy Update – July 21

Hi everyone,

It’s a muggy, sticky day in PEI…looks like rain, but not much has arrived yet.  There are a number of growers who would welcome another half an inch or so this week, while there are others that have probably had enough for the moment and just want to keep up with their spray schedules.

Undoubtedly, the crop is off to one of the best starts that we’ve seen in a number of years.  The majority of acres have closed rows and are now in flower, and tuber initiation is in full swing.  Moist soil conditions are resulting in above average tuber numbers being initiated, and it should also result in fewer incidences of common scab this year (we hope!)

If I look at rainfall so far, here is some of the data we’re seeing up to July 20:

Location 2021 Rainfall (mm)
May 1 – July 20
Historical Average (mm)
May 1 – July 20
Mill River 216 231
Summerside 244 242
Charlottetown 233 240
Souris 271 249

In terms of Growing Degree Days (>5C):

Location 2021 GDD
May 1 to July 20
Historical GDD
May 1 to July 20
Summerside 762 705
Charlottetown 713 707
St Peters 726 659

As you can see…we’re at about “normal” for rainfall so far this growing season (east is up about 10%) and we’re mostly ahead by 8-10% on GDD (except for Charlottetown).


Spore Trapping Update:

Spornado Results for Monday, July 19thAll sites negative for Late Blight

Airspore Results for Monday, July 19thAll sites negative for Late Blight

Airspore Results for Alternaria/Bortrytis (July 19th)

Location Early Blight
(A. solani)
Brown Spot
(A. alternata)
Bortrytis cinerea
West Prince (ave of 5 sites) 90 56 19
East Prince (ave of 4 sites) 23 9 18
Queens (ave of 4 sites) 2 2 11
Morell/St Peters (1 site) 0 0 22
Eastern Kings (4 sites) 0 0 3

Good news that we don’t have any late blight spores showing up yet, despite weather that is prime for late blight infection.  Ontario is the only province so far that has reported finding late blight spores, but no foliar infection has been reported yet.

It appears that we’re hitting the first spike of early blight and brown spot in West Prince, and it will likely work its way across the province, as spore counts are very low or zero east of Hunter River.

For a story from CBC on spore trapping in PEI:


SpudChat:  Scouting Meeting Review #2

This week’s SpudChat episode is a recap of this week’s Fieldworker Meeting held yesterday (Tuesday) morning.  I chat with Lorraine MacKinnon and Christine Noronha about what we heard from a good group of agronomists, scouts, and reps (both in person and online). I encourage all agronomists, scouts, scientists and reps to attend these meetings every two weeks, organized by Lorraine and the PEIDAL.

To check out this week’s episode, visit or download in your preferred podcast app.


Looking Ahead:

We’re quickly getting to the end of July…how the weeks fly by.  As summer rolls on, a few things to keep in mind:

  • If you have fields that are struggling with compaction, the summer is a good time to think about subsoiling.  I’m not an advocate of subsoiling every acre…but assess your fields, see where there are compaction issues, and consider the timing of subsoiling when the soil is dry to ensure that you fracture those compaction layers.  Subsoiling after grain harvest or after 2nd cut hay can be a good time, especially if you have something growing in the field that can grow into those fractured layers.
  • If we get into a run of damp, hot weather in the next couple of weeks, keep an eye out for white mold (sclerotinia), particularly in rotations where potatoes are close in rotation with soybeans, canola, mustard or peas.  There has been more white mold than usual in Ontario this summer due to their hot, wet weather in July.
  • For those growing mustard as a biofumigant crop…the mustard in our trials is maturing really fast!  As quick as 6 weeks to peak flower this year.  For maximum biofumigant effect, you want to chop and incorporate mustard before it makes hard seed pods and loses much of it’s flower.  Also, having adequate soil moisture at the time of incorporation is key.  In much of the province, there is enough soil moisture right now for biofumigation.
  • The moderate temperatures and good soil moisture levels should result in your potato plants being able to access nutrients more efficiently from the soil this year than in past years.  Nitrogen management this year will be different than the last few years, where a lot of foliar N was used to get the crop through very dry periods.

Have a great rest of the week,