Crop Conditions – Week of May 1, 2023

A field of winter cereal rye planted into corn silage. Ponded water is visible on much of the surface.


Overall, April rainfall has been slightly higher than average. This week, cold and wet weather slowed crop and planting progress. Eastern Ontario received above average rainfall, while most of the rest of the province had average rainfall.

Winter Wheat

Weather conditions have caused winter wheat growth to stall. The crop continues to look very good overall, with most fields around growth stages 30-32. This is still a good window for plant growth regulator (PGR) and early fungicide applications, though weed control should be prioritized in those fields experiencing pressure as application windows open. Check herbicide labels to match crop staging. If under-seeded red clover is not advanced enough for spraying, the recommendation is to prioritize weed type and staging as a decision factor. Where appropriate, PGRs should be applied sooner rather than later as earlier timing helps to strengthen the base of the stem in addition to shortening internodes.

Wet weather presents some risks to a wheat crop – notably disease and nutrient uptake and availability. Disease incidence has been low so far, possibly because high moisture has been accompanied by low temperatures which slow disease development. Forecasted warmer temperatures may increase disease pressure, which can be managed with timely fungicide applications. The proper T1 fungicide timing (GS30-31) is or will be passed in most fields, but with disease pressure currently low this shouldn’t be a concern. Fungicides typically remain effective for about 14 days. Ontario data has shown that T2 and T3 fungicide applications generally result in a larger yield response than T1 timing. These should be targeted at GS 37-39 for T2 (flag leaf), and GS 58-61 for T3.

Saturated soils can result in nitrogen deficiency in wheat, either from reduced uptake or increased losses. The risk of losses from denitrification is currently very low, as it is related to temperature, but N deficiency could become a bigger issue if soils continue to remain saturated while wheat progresses into a stage of rapid N demand.

Spring Cereals

The planting window for spring cereals is closing for southern Ontario, though the target date for northern Ontario is still a week away. Wet conditions and unfit soils prevented some planned spring wheat acres from being planted. Those acres are now being switched to other crops, mostly corn and soybeans. Spring cereals that were planted in the past few weeks have emerged and are looking good.


Little progress has been made in corn planting since the brief planting window in mid-April. While some unseasonably warm conditions last month made it seem as if the season was well underway, it’s not at all uncommon for corn to be largely unplanted in the first week of May. The earliest recommended date to switch from full-season to lower heat unit hybrids is the week of May 15th for areas that average fewer than 2800 crop heat units (CHUs). In places with more than 3200 CHUs that switch date is not until May 30th. Until June, soil conditions should always trump the calendar date for deciding when to plant corn. Soil conditions are critical to good corn emergence and uniformity, and compaction damage to the seedbed can negate any benefits to planting corn early. None of the corn planted in April has reportedly emerged yet.

Some observations have been made of black cutworm populations emerging. Populations are low, but growers with rye cover crops are recommended to scout those fields.


A similar situation to corn – some fields of soybeans were planted in April, but fit acres were mostly on lighter soils. The early-planted crop has yet to emerge.


Alfalfa stands overwintered well again this year in southern Ontario and were able to benefit from an early warm spell. High forage stocks in some parts of the province may reduce the perceived need for new seedings, but it’s worth considering the age of stands currently in production from a risk management perspective. Older stands are more susceptible to winterkill, so planting some of those wheat acres into new alfalfa can help reduce exposure to risks of a bad winter. To maintain high yield potential and reduce the cost per tonne of forage, alfalfa stands should be terminated after 9-12 cuts. Winter cereal forage harvest is likely to start in the next two weeks.

Breakfast meeting minutes


Ridgetown Ag Breakfast Meeting                                                           May 3, 2023


This graph is called a boxplot. Note that each timing comprised of a massive 312 plots!  Why the incredible yield variability within each timing?  Answer: yield responses were most associated with disease control. For example, where diseases were minimal, the yield response for a T1 application (GS30) was zero. Note the callouts on the right-hand side of the figure to explain the boxplots.  If you were planning a fungicide application at GS32, then it may be safe to assume an average response between T1 and T2.

Edible Beans

  • Chris Gilliard shared research into azuki bean management that is ongoing
    • Planting rate and date, nitrogen timing and rate, starter fertilizer banding, S, Mn, Zn
    • Initiated by Meghan Moran
  • New grad student researching SCN in dry beans
    • Huge difference of tolerance between classes of beans

Hort crops

  • Early planted peas have emerged
  • Plans to start planting tomatoes as early as next week if weather cooperates

Weed control – Peter Sikkema

  • In dry beans, absolutely need to start with soil applied herbicides
    • Treflan/Dual + Permit or Pursuit
      • Pursuit – better for annual grass pressure
        • Activity on EBNGenerally may look a bit better than Permit
        Permit – better for LQ, RW
        • Gentler on crop than Pursuit
        Avoid 4 actives in tank, may overload the ability of the dry bean to metabolize the herbicides
        • Can cause crop injury and yield loss, injury varies by dry bean market class
  • Azuki beans
    • More sensitive to Group 15 herbicides (Dual & Frontier) than other dry beans
    • Do not apply Eptam or Basagran
    • Azuki bean is more tolerant to Pursuit; can use soybean rate
    • Metribuzin – azuki bean are more tolerant than other dry bean market classes
      • 280 g ai/ha – reasonable rate
  • Group 15 (Dual & Frontier) injury in dry beans looks similar to metribuzin injury in soybean

Agricorp update

  • SW, SC, Niagara – Winter Wheat
    • Total of 72 damage reports – around 7000 ac
      • ~2.1% of insured acres
      • 33 reported last fall – likely gone away
      • Damage reports don’t always translate into payment
  • Deadline:
    • Winter wheat – add coverage – May 10
    • Apply for, make changes to Production Insurance, Risk Management – May 10


Cobourg Breakfast Meeting                                                                                May 2, 2023

  • Field conditions are wet. Rainfall over the last few days ranges from about 25 mm (1 in.) to 75 mm (3 in.) as you move from west to east across the region.
  • Winter cereals have stalled. Herbicide applications should be priority when conditions improve later this week. Plant growth regulators are next in terms of importance. Cool conditions and slow growth should help forage cereals hold onto quality.
  • Grasses are growing quickly, although forage legumes could use some more heat to drive development.
  • Some growers have stopped seeding spring cereals and plan to start corn and beans when field conditions are fit.
  • No concerns about timing yet. Most corn and beans were seeded around May 10th in the last couple of years, and some of those fields had record yields.