Ontario Crop Report – Week of May 30, 2024

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A corn field at 3-leaf stage
Figure 1. Despite the wet environments, planting has continued and much of the corn crop has emerged quickly and in good condition.
Field Conditions

It continues to be a frustrating spring through much of the province. Frequent precipitation has continued to cause delays in tillage, planting, and spraying in some areas, and weather earlier this week has shut down field work once again in many areas.

However, with 3–5-day windows of good weather, many producers have covered a lot of ground in a short time, especially on lighter soils that have avoided heavy rainfall. Farms on heavier clay soils continue to face difficulties, but there is still time to get crop in the ground.


Wheat growth and development continues to be more advanced than normal, with most of the winter wheat in the province either close to or fully headed out. Overall, the crop continues to look good, and yield potential looks strong.

Stripe rust has been in several locations throughout Ontario. This disease is critical to control, especially in susceptible varieties where it can cause major yield loss. Its arrival may complicate T3 fungicide application in fields that have not yet reached optimal timing for fusarium head blight protection and DON reduction. Stripe rust is a fast-moving disease and has the spread through a field within a few days. Scouting is an absolute must ahead of T3 fungicide application. See the Ontario Cereal Crop Committee performance trials at www.gocrops.ca or check with your seed supplier for ratings for both stripe rust and fusarium head blight to prioritize action if necessary.

There have been some incidents of surfactant injury reported from T3 fungicides. Often the problem looks worse than the yield loss that can occur. Physiological fleck (figure 2.) is also
appearing in several fields, and the two can be misidentified as well as confused with disease symptoms.

Figure 2. Physiological fleck in winter wheat. This is often misdiagnosed as leaf disease or surfactant injury.

Root rots diseases are also appearing due to wet conditions and can be confused for viral infections or other disease as well. Lodging is likely to be a concern through the grain fill period. Heavy plant biomass due to good growing conditions this spring has already led to some small areas of lodging in fields, particularly in hollows with high yield potential. Varietal differences in lodging score may be of importance to prioritize harvest in the coming weeks.


Harvest of triticale and rye is wrapping up, while first cut of alfalfa has started. Yields have been excellent so far, but quality has been difficult to manage as rains have delayed cutting past the optimum stage, or the cut crop has gotten rained on.

Alfalfa weevil populations are very high in some fields. Control may be necessary if populations are high and harvest is more than a week away. See the Crop Protection Hub for details on registered products for control.

Forage gas poisoning is a threat that exists with the early start to ensilage season. One incident has been reported already, it’s important for producers to keep this in mind and not be working alone where the threat exists.


Corn planting is likely around 80-90% complete across the province, although this number varies drastically depending on local conditions.

Some areas have planted very little of their intended acres, although there remains time in many locations for a successful corn crop. In longer season areas in the southwest, agronomists are recommending continuing to plant corn on intended acres rather than switch to soybeans, especially in fields that have had continuous soybeans for several years in a row.

Corn planted earlier in the spring is up and looking very good, with some of the earliest crop at the 5-leaf stage already. Crop planted in the last couple of weeks has enjoyed rapid emergence due to warm soils, out of the ground within 4-5 days in some cases.

Some fields with emerged corn remain weedy as sprayers have had trouble covering acres this spring. Data from Peter Sikkema at the University of Guelph – Ridgetown Campus has shown that in fields with high weed density, that yield losses of 1.7 bu/ac per day can occur for every day that control is delayed past emergence. Timely control of weeds is crucial right from emergence in corn. 


Soybean planting is highly variable across the province as well, with some producers having yet to plant an acre, and producers in drier areas having completed planting. Estimates for planting progress across the province is in the 50-70% range.

Changing varieties is not necessary unless planting is delayed into July. Full season soybean maturity recommendations are conservative in Ontario and allow for later planting. The main reason to not switch to shorter maturing varieties is that shorter maturing varieties have lower yield potential. A reduction of one full maturity group (1.0 MG) will drop yield potential by about 5 bu/ac. If the field is intended for winter wheat a shorter maturing variety has likely already been selected to facilitate timely wheat seeding. If seeding wheat this fall is an absolute priority a further reduction may be warranted if soybean planting is delayed past June 15th. In the relative maturity grouping system used for soybeans each decimal place represents a 1-day delay in maturity in the fall. For example, a 1.5 MG variety will mature 4 days earlier than a 1.9 MG when seeded on the same day. Weather conditions will influence the exact difference in maturity but generally speaking a 0.5 MG shorter maturing variety than a full season is considered adequate for timely wheat seeding.

Soybeans have begun to emerge as well, with some already in the 1st trifoliate stage. Due to warm temperatures and moisture, soybeans have emerged rapidly.

In some cases a mix of warm temperatures and rainfall have caused producers to miss pre-emergent herbicide applications. In fields with heavy weed pressure, this limits the products available to control large weeds to prevent yield loss. IP soybean producers who miss pre-emergent herbicide applications will be severely limited with product choice.

Agronomists are recommending that pre-emergence herbicides are absolutely critical to control weeds in soybeans, and should be done prior to planting if there’s a chance of missing the application window post-planting. When dealing with problem weeds such as glyphosate-resistant Canada fleabane, there are no good post-emergence herbicide options for control in IP soybeans.

Edible Beans

A small number of acres have been planted, but the majority of intended edible bean acres are still to get in the ground. There has been increasing interest in acres overall, and some producers may end up switching fields from corn to edible beans if delayed much further.


As weeds get larger, they become much harder to kill. Correct product and rate selection becomes critical as management plans are adjusted based on weed type, density, and size. Use of highest labelled rates is recommended with larger weeds. With higher weed density, it becomes more important to maintain good coverage with herbicides, which may involve using higher water volumes, slowing the sprayer down and lowering the boom closer to the target.

With post-emergent applications especially, a reminder from agronomists that with more products added to a tank-mix, there is a greater chance for crop injury from the herbicide, in many cases without an increase in weed control. Adjuvants are important for use with certain herbicides, but care should be taken to ensure they don’t cause injury from improper use. The Crop Protection Network has provided some excellent guidelines for proper adjuvant selection and use, located here.

As a general reminder, only use registered products with labelled rates and tank-mix  partners for weed control in Ontario. Some product active ingredients are registered in the US, but often with different formulations and rates that can cause crop injury on this side of the border. Always read and follow label directions! 

Agricorp report

For Production Insurance coverage, crop planting deadlines are June 15th for corn, and June 30th for soybeans. The deadline for reporting unseeded acreage is June 15th, and deadline for reporting actual acres of spring-seeded grains and oilseeds or new forages is June 30th. Report acres as soon as possible to avoid busy times at the deadline.

Breakfast meeting minutes


Field conditions:

  • Variable, but wet overall. Some areas have had 4” of rainfall over the past two weeks, Cairo had 7.5” last week alone.

Planting intentions:

  • Some switching of hybrid maturities, but unsure of when will be able to get back into the field. Producers don’t want to be stuck with high moisture, low test weight corn if an early frost comes in the fall.
  • Seed supply looks good for shorter season hybrids. In high CHU areas, there is still plenty of time for a full season hybrid to reach maturity.


  • T3 fungicide application wrapping up, although rain has interrupted application. Newer products still have activity for fusarium head blight/DON control, even if a bit past the optimal window for application. Be aware of pre-harvest interval on label.
  • Watch out for tank contamination. Reports of injury from T3 fungicide application following pre-emerge herbicide tank-mix when following soybean spraying.


  • Rapid emergence in corn planted over the past couple weeks, many fields out of the ground within 4-5 days with warm soils.
  • Several fields with no residual herbicide applied in dire need of clean-up.


  • Rapid emergence in soybeans as well, some out of the ground with 4-5 days as well.
  • Issues of missed application of pre-emergence herbicide are reported. With IP soybeans, this is a very big problem as there are very limited options for weed control.
  • Producers are reminded that products like Enlist or Liberty have a time and a place, but must be used as part of a program and large weeds will not be controlled by the herbicides.
  • “We’re still dealing with a Roundup hangover” – John Seliga, discussing the challenges producers face when changing mindset to more expensive herbicide programs compared to single pass of glyphosate.

Horticultural crops:

  • 75-90% of tomatoes are estimated to be planted.
  • Black cutworm damage has been identified in sugar beets.
  • Frequent rain events continue to slow field work. Producers are stressed because they haven’t got as much done as they’d like. Custom applicators and retailers are stressed because they’ve been working flat out trying to keep up to demand.
  • Wheat is heading out. Fields that missed a nitrogen application are showing deficiency symptoms, but otherwise the crop looks good. A T3 fungicide application will be important to manage disease pressure in this warm, wet spring.
  • First cut hay has started. Yields so far are excellent. Quality may be a challenge due to rain: either the optimum cutting date is missed because field conditions are too wet, or the cut crop gets rained on.
  • Corn planting progress is variable, but likely about 75% done across the region between Highway 400 and Kingston.
  • Soybean planting progress also varies with soil type, but estimates are about 50% done.
  • Weed control is a challenge, especially since ideal herbicide application windows are passed or will pass soon. Remember the correct mixing order (WAMLEGS) to prevent problems in the sprayer.
  • Pest monitoring networks across the U.S. are showing above-normal insect pressure already this year. The mild winter enabled many pests to overwinter that normally don’t handle Ontario’s cold winters well. Scouting for insect pests will be very important going forward.
Mount Forest

Planting Progress

  • The group was enthused with how much progress has been made in corn and soybean planting since the last meeting given the rainfall and fitness of soils for planting moisture wise.


  • Rains continue to frustrate the area although for the most part quite exceptional how much crop has been planted in the last two weeks between the rain events.
  • There is a lower temperature period coming up that will slow down crop growth and perhaps some insect and disease issues.
  • Regionally Simcoe, Dundalk highlands and west of Waterloo stick out as the places with the most planting left to complete given the amount of damp soils.
  • Low temperature forecast (2C – 5C) for  the morning of May 29th are likely not a concern for grain crops


  • As the fields dry to get sprayers in the field, there will be work in all crops so the pressure is high to get everything done timely and without injury based on sprayer clean out issues or soybean trait program miscommunication
  • Proper tank clean out remains a priority, especially when switching to T3 sprays or between soybean traits
  • While proper clean out is important for all herbicides used, clay based (dry) formulations tend to be the hardest to clean out.
  • For T3 fungicide spraying, there was comments that awned wheats are more difficult to get uniform fungicide coverage on the heads and that product, surfactant, water volume, and nozzle selection are all important maximize efficacy


  • Across the region upwards of 90+% is planted although there are pockets with much lower numbers due to soil type and rainfall.
  • In general it’s the “tough” pockets of land that are still to be planted, some of these acres have or are switching to soybeans but some will still plant because of feed needs
  • A lot of corn went in under a bit wet to too wet conditions but the continued wet weather has prevented that from impacting emergence uniformity timing and population to date, the remainder of the summer will be dependent on the weather.


  • Variable planting progress but still 60-70% on average completed with range of 0-100% again a function mostly of soil type and rainfall.
  • Stages run from just planted to approaching 1st trifoliate.
  • Although soil conditions may have been less than ideal at planting, the warm temperatures ensured rapid emergence and there was little crusting of soil to date.


  • Differences in growth stage across the wide geography covered by the group, but in general, heading is near or started and urgency to apply T3 runs from this past Sunday through the coming weekend.
  • From scouting reports, fields with a T1 or T2 fungicide are showing less susceptibility to stripe rust at this stage/timing
  • The weather makes it a DON year and with significant acres of “bin” run seed and older varieties across the area, timing of T3 should likely favour the head diseases due to absence of newer varieties that have some breeding protection built in.
  • Some questions about true army worm but other than Chatham-Kent with trap levels above 30, most areas are in the low single digit levels.
  • Even so with the harvest of forage cereals and now legumes, we might see a move to cereals so scouting is important
  • Cooler conditions happening with low temp threat overnight Wed, May 29th could potentially have some impact on wheat which is heading, but thought that the crop is still early in the heading period and hasn’t started anthesis/flowering

Edible Beans

  • Some have been planted but still low, timing is good coming up and hopefully allows them to get their tillage and PPI herbicide programs applied


  • Dairy triticale and rye essentially harvested although second crop planting in those acres relatively low
  • Some fields of forage hay have been cut and already seeing rutting from that operation let alone what will happen when harvesters and wagons get in the field
Northern Ontario

Colin Elgie, Soil Fertility Specialist, shared info on nutrient deficiencies commonly observed and some that are being observed in southern Ontario now. Soil moisture helps roots access nutrients but if there is too much water, mobile nutrients may move too far down in the soil profile and become unavailable to plants. With the excess moisture in southern Ontario at this time, nitrogen deficiency in corn has been observed. Nitrogen deficiency appears as yellowing of lower leaves starting at the midrib of corn leaves. Similarly, nitrogen deficient canola will have yellow or pale green lower leaves. Sulphur deficiency may be observed in cereals and appears as yellowing, stunting, shorter leaves and shorter internodes, starting from the top of the plant. Alfalfa with sulphur deficiency will be yellow at the top of the plant, and boron deficiency can appear as reddish discolouration on new leaf tips as well. Colin shared some photos of nutrient deficiencies.

Christine Brown, Field Crop Sustainability Specialist, shared details of a forage project she is involved in. Generally, the stands have gone from average 80 stems per square foot in the first year to 40-45 plants per square foot in year 4.  Frequent manure application resulted in continued good growth and yields and adequate fertility.  She has noted that alfalfa stem counts declined by about 50% since last fall where chickweed pressure was high.  Dandelion, shepherd’s purse, and chickweed tend to establish where there are gaps in the field and/or just after hay is harvested. In the wheel tracks of manure applicators applying manure in late September, alfalfa winter survival is very low because the crowns were damaged and could not recover enough to survive winter. Severe winter kill following a wet fall period in 2021 resulted in some producers using Italian rye to fill in areas of the field that the alfalfa did not survive, rather than terminating the field. These producers are very happy with the forage yields and are keeping the stands longer than they normally would.


On June 6 Christian Farmers Federation of Ontario is hosting a Wellness Dinner focused on how to recognize signs of mental health issues and what to do to provide support. Lauren Van Ewyk, co-founder and CEO of the National Farmers Mental Health Alliance, will speak at the event as well as Diane Bergsma, from a farm family that lost a son to suicide. All are welcome. Contact CFFO or Pierrette Desrochers pierrette.desrochers@ontario.ca to reserve a spot for dinner. 

Regional Updates


Producers participating on the call are done planting corn and moving to canola next week; 30% done seeding. Spring has been more wet than normal. Crops planted later tend to do better because they are seeded into warm soils and grow vigorously early in the season. It was noted they are concerned about clubroot in canola and considering how to manage risks of that disease.


Seeding is complete and sprayers have been out in winter wheat. Some spring planted crops are starting to emerge with recent warmer conditions. Grassy forages are being harvested, particularly for dairy operations. Alfalfa harvest will happen soon. First cut this year is about a week later than.

Temiskaming and Cochrane

A relatively early start to seeding in these regions, especially Cochrane. Seeding began mid-May and is essentially complete now. Canola is emerged in some fields and soybeans are just beginning to break through. The temperature dropped to zero or below last night so crops will be checked for damage. Forages have not been cut yet, but some fall rye is at boot stage and will be cut soon. Recent rains have put a halt to field work.

Thunder Bay

Wheat was seeded at the Lakehead University Research Station (LUARS) in early May and producers were seeding in mid to late- May. Seeding is nearly complete, and there has been good emergence although there was some crusting. Growth is slow because nights have been cool and recent daytime temperatures have topped out around 17 degrees C. Trials at LUARS this season include testing biologicals, sorghum-sudangrass seeding dates, and a polymer coated urea that is manufactured in Ontario.

Rainy River

There was nearly 3” of rain last week and not enough heat to dry the soil quickly. Fields without tile have not been touched, and fertilizer has not been applied to forages, and producers are behind on spraying.


Prior to rains 50% of cereals were seeded and producers were grateful for rain, but now precipitation is 150% of normal and there has been snow in Brandon area. Crops on clay soils are suffering and there is standing water. It was noted that canola seeding dates have generally moved later in Manitoba, after corn seeding. Modern canola hybrids don’t suffer as much during flowering in summer heat as older open pollinated varieties did, and faster growth with seeding into warmer soils helps mitigate flea beetle damage.

Weather Summary – Thursday May 23 – Wednesday May 29, 2024

LocationHighest Temp (°C)Lowest Temp (°C)Rain for Week (mm)Rain Since April 1st (mm)GDD0C April 1stGDD5C April 1stCHU May 1st
10 YR Norm (11-20)25.79.431.6191.3669376496
10 YR Norm (11-20)
10 YR Norm (11-20)
10 YR Norm (11-20)26.18.326.3169.5605319452
10 YR Norm (11-20)
10 YR Norm (11-20)
10 YR Norm (11-20)25.37.915.6166.6520247382
10 YR Norm (11-20)24.97.718.9154.2508242378
10 YR Norm (11-20)26.17.418.5151.7494231371
10 YR Norm (11-20)26.58.621.6153.6537262403
10 YR Norm (11-20)27.38.413.3159.1560287423
10 YR Norm (11-20)24.48.315.9150.2408195333
10 YR Norm (11-20)22.55.418.1127.5359168308
10 YR Norm (11-20)
10 YR Norm (11-20)20.34.332.9132.5323120247
10 YR Norm (11-20)22.26.621.9111.6385164311