Agronomy Update – August 18th

Hi everyone,

I’m back at the office this week after a week of vacation, which thankfully corresponded with some warm, sunny days.  Sunny days like we’ve been having recently, combined with adequate soil moisture in most areas, should be a recipe for significant tuber bulking this week.

I have heard reports of somewhat dry soil conditions at the surface in parts of West Prince and a few communities in Central PEI.  Other areas reportedly needed a stretch of dry weather to allow some saturated fields to drain and keep drown-outs to a minimum.  July rainfall totals were quite similar from one end of the province to the other (~150 mm) and growing degree days (GDD) were also very consistent across the province.

I’m starting to see the evidence of drown-outs in multiple fields a week or two after those heavy rains.  If you have those type of low spots with yellowing or dead plants…flag them now!  The same caution should also be taken for sprayer tracks…many of those have experienced standing water due to soil compaction.  Consider putting the potatoes from sprayer tracks at the front of the pile at harvest or in a different storage, if possible.


Notes on Crop Progression:

In my travels, I see some early-maturing varieties and seed fields starting to turn a lighter shade of green, with foliage starting to lay down a bit.  This is a good sign…it means the plants are starting to drive carbohydrates down into the tubers.  2021 will be an interesting case study in how much nitrogen is needed in many of these newer varieties in what has thus far been largely a very strong growing season.  If fields stay rank green into September this year…it may be that they had access to a bit too much N, delaying tuberization.  Finding the balance for a crop like potatoes in a dryland system continues to be a delicate dance from year to year.

For those that are combining grain this week and seeing a great underseed coming along…this would be a great time to do some subsoiling on fields that need it.  Drier soil conditions along with a growing forage crop that is just getting going is ideal conditions for subsoiling and fracturing those compaction layers.

AIM Crop Tours – September 1st and 2nd

I am planning to hold some crop tours to show some of our trials across the province on September 1st and 2nd.  I hope that growers and industry partners can join us for one or all of these tours.  Full details and locations will be made available next week, but please mark your calendars for these dates:

AIM Eastern Crop Tour (Kings Co) – afternoon of Wed, Sept 1

AIM Central Crop Tour (East Prince) – morning of Thurs, Sept 2

AIM Western Crop Tour (West Prince) – afternoon of Thurs, Sept 2


Spore Trapping / Disease Update:

Spornado Results for Monday, August 16th:  All sites negative for Late Blight

Airspore Results for Monday, August 16th:  All sites negative for Late Blight

Airspore Results for Alternaria/Bortrytis (August 16th)

Location Early Blight
(A. solani)
Brown Spot
(A. alternata)
Bortrytis cinerea
West Prince (ave of 6 sites) 7 1 111
East Prince (ave of 4 sites) 15 10 397
Queens (ave of 4 sites) 0 2 280
Morell/St Peters (1 site) 4 0 164
Eastern Kings (4 sites) 0 1 54

Last week, there were reports of foliar late blight in northern Maine (Madawaska).  It was thought to be seed-borne and contained.  Last Friday, there was a detection of late blight spores in southern Carleton County in New Brunswick.  There have not been any late blight detections in PEI this summer.  We will continue collecting for late blight spores until mid-September.

I have recently seen some evidence of early blight, brown spot and grey mold on the lower leaves, mostly in Russet Burbanks.  However, levels were relatively low.  Hot and dry weather last week and this week should make grey mold less of a concern, but it can be a breeding ground for Alternaria, so keep an eye on your fields and manage accordingly.  If you just see a little bit of leaf spotting and we’re getting closer to September, you’ll have to talk with your agronomist/crop consultant about whether additional fungicides targeting Alternaria are worth the investment if the damage is minimal.


SpudChat This Week:

This week’s SpudChat features our final Scouting Review chat of the summer.  Thanks to Lorraine MacKinnon, Eileen Beaton, and Morgan MacNeil for joining me this week.  You can find SpudChat at or wherever you download your podcasts.


Cover Crops Webinar:

For anyone interested, SpudSmart is hosting a webinar on September 9th on the topic of cover crops in potato production.  One of the speakers is Dr. Judith Nyiraneza of AAFC Charlottetown, who we have been collaborating on lots of trials with in recent years.

Click to register:  

Have a great rest of the week