Agronomy Update – Aug 11

Hi everyone,

With another week without rain… it’s unfortunately starting to get pretty critical for some fields.  I see a lot of difference between this time last week and today in certain communities.  I truly hope that we get some convective thundershowers or some unexpected rain this week as well as some rain this weekend.

I want you to know that I appreciate how stressful this weather must be for you all.  Please ensure that you reach out to the Farmer Assistance Program (902) 626-9787 or toll-free 1-800-736-8006 from the PEI Fed of Ag if you need someone to talk to.  That’s what those resources are there for.

Spore Trapping Update:

For some good news, there continues to be no sign of Late Blight in the Atlantic Northeast.  No spores have been detected in PEI, NB or Maine this season.  Our current weather is not very conducive to late blight infection.  If you are using one of the blight decision tools (Ukko Agro or Air Spore), check your reports to see if it’s recommended to space out your sprays a little longer.

Early blight and grey mold spores have also significantly decreased in the last few days across the province.  Spore results are listed below:

Table 1:  Spore Trapping Results for Monday, Aug 3rd and Wednesday, August 5th:

Community Fri, Aug 7
Early Blight
# of spores
Mon, Aug 10
Early Blight
# of spores
Fri, Aug 7
Grey Mold
# of spores
Mon, Aug 10
Grey Mold
# of spores
Elmsdale 9 4 22 0
O’Leary 0 0 9 27
Wellington 13 0 0 0
Summerside 0 4 18 13
Kinkora 67 0 0 0
Meadowbank 36 4 36 0
New Glasgow/Rustico 9 0 4 9
Oyster Bed/Winsloe 9 0 13 4
Souris 0 0 249 0
Elmira 31 0 1058 360
Dundas 4 0 1533 560
Stratford 0 0 9 22
Average 15 1 246 83

Looking Ahead at Cover Crops:

Many growers are looking ahead at cover cropping for this fall.  Cover crops have a myriad of benefits:  preventing soil erosion, preventing nitrate leaching, building soil organic matter, suppressing weeds, and suppressing soil-borne diseases for some crops.  There is a good article from Ontario about cover crop benefits and selection here (Top Crop Manager article).

There are many growers looking at planting cover crops in the next couple of weeks following peas or grains or after working up a forage field ahead of potatoes next year.  If planting a cover crop in late August/early September, you have more options when it comes to crops that can get established in the fall.  For a PEI-specific decision tool on cover crops, visit

Some possible options:

  • If worried about wireworm in your area, using brown mustard as a fall cover can work well.  Up the seeding rate a little (~12 lbs/ac) to get a good cover before winter.  Doesn’t work well after the first week or so of September.
  • Other brassicas like oilseed radish, winter rapeseed, tillage (daikon) radish, and kale also work well if planted in late August/first week of September.  They can be also be combined at low seeding rates with other species like cereals to maximize your biomass.
  • Spring cereals like oats and barley make good fall covers ahead of potatoes, where you don’t want to have to terminate the crop in the spring.  Oats seem to be a little scarce this summer, but they usually require a little less fertility than barley and are more weed-suppressive than barley.  Both oats and barley can be planted until late September to get a decent catch most years.
  • Consider adding some winter peas to a mix with cereals or a brassica.  Helps fix nitrogen to feed the cover crop.
  • Some growers have had success with annual ryegrass as a fall cover.  This year, I have seen a lot of establishment issues with ryegrass.  It does not establish well in dry soil and the weeds can get ahead of it.  Also make sure you are using annual ryegrass…Italian or perennial ryegrass can become a weed issue.

If you’re looking at cover crops to follow potatoes, the gold standard in PEI has been fall rye.  It will establish until Oct 15th in an average year, is generally winter hardy, and will regrow in the spring when your soil is prone to water erosion.  If you get a good catch of fall rye that regrows in the spring, it will grow aggressively in May and June and help keep weed pressure down.  This might be a good solution for fields that are going into a late-seeded crop like sorghum sudangrass or pearl millet in mid to late June.  If terminating ahead of an earlier seeded crop like barley, corn or peas, a herbicide application is recommended.  Mowing will generally only terminate fall rye if done after it’s out in head (reproductive stage).  Of course, you can choose to harvest some of the rye as well and reduce your cover crop costs!

Other cover crop options following potato harvest:

  • Winter wheat.  For potatoes harvested in September, winter wheat is a great choice.  You will likely notice a difference in yields for winter wheat planted in early October.
  • Winter triticale (hybrid of wheat and rye).  Establishes a little later than winter wheat, not quite as late as fall rye.
  • Winter barley.  I don’t know a lot of growers who have experience with winter barley in PEI, but I’m looking for a few growers who would be interested in trying a small acreage of winter barley this fall as part of the Living Labs project (give me a call!)
  • Spring barley/oats.  These will generally establish until early October but they terminate over winter.  Good for earlier harvested acres.  The later you seed, you will need to increase the seeding rate. Same goes for broadcast vs. drilling seed.
  • Most brassicas are not recommended after the 25th of September.  In our Living Lab trial fields where brassicas were planted in late September, they did not establish well.

Additional Notes:

  • Christine Noronha reports that hot, dry weather like this can be prime for tarnished plant bugs.  Keep an eye out in your scouting.  Also can be favorable for leafhoppers.
  • If you have any trial fields with Morgan and I as part of AIM, Living Labs, etc and you anticipate needing to make some changes to harvest dates, tillage dates, etc, please give us a call before you head to the field so we can make sure we capture all necessary data.
  • For everyone combining and baling straw….STAY SAFE!  Make sure you have a fire extinguisher in the combine/tractor!  Take extra time to make decisions that keep you, your staff, and your family safe.

Let’s all hope that rain is in the offing this week.