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Crop Assessment Results

16th Annual Great Lakes Grain Crop Assessment Tour Highlights Variability Across Ontario Fields

Southwestern and Eastern Ontario – September 9th 2025 – The 16th Annual Great Lakes Grain Crop Assessment Tour provided valuable insights into the state of crops across Southwestern and Eastern Ontario. Organized by Great Lakes Grain in partnership with AGRIS Co-op, Central Ontario FS, Coop Embrun, and other FS Member Co-ops, the tour covered nearly 800 fields, giving participants a first-hand view of crop conditions and yield potential.

This year, variability across the region was significant as many areas experienced uneven rainfall. Early planting and uniform corn stands generally led to stronger performance. Across most counties, crops were greener and slightly behind normal maturity. Pest pressure remained manageable, and disease incidence was low. Yield counts were not conducted in the Central Ontario counties most affected by extreme drought, an area that typically represents about 10% of the province’s acres.

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Grain Originator Observations:

  • Heather MacLeod (Essex, SW Kent)
    “Earlier planting and uniform stands proved most beneficial, while drilled soybeans showed more variability and higher seed costs. Crops are maturing slower than normal, with regional differences, shorter crops north of Hwy 401 from drier weather, and stronger growth in South Essex with timely rains. Aphid pressure was noted but kept in check, and no major disease issues were found, though wet silks could heighten ear rot risk. September weather will be critical for finishing kernel depth and pod fill.”
  • Serenity Marshall (Chatham-Kent, SW Middlesex, West Elgin)
    “Crops looked mostly average to slightly above, with a few standout fields. Fields were very clean with minimal disease, though some white mould in dense soybeans, minor SDS, and late tar spot in Muirkirk/Duart were noted—unlikely to affect yield. Beans were smaller with fewer per pod, and corn showed smaller kernels but high counts. Overall, crops are greener and behind pace, with much of the corn still in milk/dough stage. A hot, dry September will be key to finishing strong.”
  • Heather Miller (Lambton, Middlesex, Elgin)
    “Soybeans in Lambton are average with 2–3 beans per pod, while corn is solid but still in milk stage and needs a strong September finish. Middlesex and Elgin showed slightly above average soybeans and strong corn, driven by early planting and good kernel counts. Beans have just started to turn, and overall crops are very clean with little tar spot or insect pressure. Corn yields look promising with minimal disease. Around home (Strathroy) crops are among the best seen this season.”
  • Chad Homick (East Elgin, Haldimand-Norfolk, South Oxford)
    “Crops in the region are highly variable and largely disappointing. Drought and heat have taken a heavy toll on both corn and soybeans, with some corn ears dropping prematurely. Spider mite damage was also evident in soybean fields, further pressuring yields.”
  • Dave Snowdon (Huron, Perth, Bruce, North Oxford)
    “Rainfall made the difference this year, with areas that caught showers showing solid averages. Corn showed notable tip-back and widespread smut, while soybeans changed dramatically from Week 1 to Week 2, with clear colour shifts across many fields.” 
  • Jim Irvine (Grey, Wellington, Dufferin, Peel, Simcoe)
    “Crops were more advanced this year compared to last in the counties checked. North Simcoe faced the biggest struggles, while most other counties are on track for average yields.” 
  • Sydney Lemoyre (Ottawa-Carleton, Leeds & Grenville, Prescott & Russell, Stormont, Dundas & Glengarry, Lanark)
    “The 2025 Great Lakes Grain Crop Tour in eastern Ontario showed corn slightly below previous years due to drought, though many fields remain strong and could finish well with steady September weather. Soybeans were mostly average, with southern areas and lighter soils seeing some yield loss, while Embrun fields showed the best potential. Pest pressure, including western bean cutworm, was minimal. Overall, despite challenging weather, eastern Ontario crops are in good condition, and a solid harvest is still achievable.”

Looking Ahead

Great Lakes Grain and partner cooperatives leverage the expertise of our Grain Originators and the insights of our Crop Specialists to give farmers a powerful, collaborative advantage—helping them make informed decisions, maximize crop potential, and develop effective grain marketing plans for the 2025 and 2026 crops.

Agronomy Assessment

In 2025, yields will be as variable as the rainfall. Not every field with low rainfall will underperform, and not every acre with abundant rainfall will be high-yielding. We challenged some old adages such as “plant in the dust, the bins will bust.” While this is true to some extent, rain is still required at some point. Rain makes grain, but the questions are: when will it come, and how long will it last?

Our fields are inherently variable. A host of abiotic and biotic stresses interact with soil features and management practices to amplify variability. The challenge is knowing what we can control and what we cannot. Each year, we see the benefits of complex rotations, diverse tillage practices, residue management, and the wise use of organic amendments such as compost, manures, and cover crops. We see differences in agronomic programs, such as whether soil sampling and nutrient recommendations are followed. Weed control programs also vary, impacting resistance management. Best management practices consistently show greater resiliency in soil health and more stable crop performance year after year. By minimizing stresses, we maximize relative yields. There is always something to learn in the fields, which is part of the reason for the assessment tour. Not every challenging acre is simply about rainfall. Careful observation and in-depth analysis always lead to more meaningful insights going forward.

With the aid of satellite images and NDVI (Normalized Difference Vegetation Index) maps, which show levels of crop biomass and vigor, we can pinpoint areas during the season and apply agronomic knowledge to troubleshoot differences in growth across the landscape. When fields contain a mix of soil textures, such as sandy knolls and loamy low slopes. The impacts are obvious in dry weather, as sandy areas show drought stress. Beyond moisture, sandy soils can also be inherently low in pH, potassium, magnesium, manganese, zinc, and nitrogen. These nutrient shortages, combined with dry conditions, add further stress and reduce yield potential. A soil testing program every four years, guided by the 4R Nutrient Stewardship principles (Right source, Right rate, Right time, Right place), is an important management tool to mitigate these issues. With drier weather this season, we observed reduced uptake of nitrogen and potassium, shown by chlorotic lower leaves. On the other hand, limited rainfall also meant there was very little nitrogen loss in fields.

We tracked the development of major foliar pathogens such as Tar Spot and Northern Corn Leaf Blight (NCLB) using the Spornado trapping network and the Agtrinsic disease modeling program. Managing foliar disease requires considering the Disease Triangle: a susceptible host, the presence of spores (many of which are endemic), and favorable environmental conditions. The Agtrinsic model incorporates crop type, planting date, hybrid, growth stage, spore counts, and weather data to produce a disease risk profile visible to farmers to aid fungicide decisions. This year, conditions indicated a low risk of Tar Spot and NCLB during the critical R1 application window. Dry weather and high temperatures kept infection pressure low. Although some late-season Tar Spot has appeared, it is likely too late to have much impact on yield.

Corn planted in early April is now well into dent stage, with a 50% milk line suggesting physiological maturity and black layer formation within about 14 days. Mid-May planted corn will require another 20–24 days to reach black layer.

Soybean fields showed similar variability. NDVI maps again proved valuable for scouting activities and to learn things with your trusted advisor. Soil texture differences created nutrient challenges, compounded by the presence of Soybean Cyst Nematode and Sudden Death Syndrome. The Spornado traps also tracked White Mold (WM) and Frogeye Leaf Spot (FLS). WM incidence was mostly confined to fields with a history of infection, while FLS was more widespread and detected at medium to high levels. Severity in most fields was spotty, but it is worth monitoring closely, as FLS in the U.S. has developed resistance to commonly used Group 11 fungicides.

Colder nights this past week, often dropping below 10°C and sometimes below 5°C, slowed respiration and triggered soybean senescence, moving plants rapidly into R7 and R8 maturity. Some fields may be ready for harvest within two weeks. However, green stems may present challenges at harvest time. This occurs when limited pod and bean numbers leave sugars in the stem, keeping it green and making harvest more difficult. Insects and viruses can also contribute to green stem issues.

Another area of interest in soybeans is row spacing and its effect on yield. This year, 38% of fields were drilled at 7.5 inches and averaged 54 bushels per acre. Forty-nine percent were planted in 15-inch rows, averaging 47 bushels per acre. Normally, we do not see this much spread between row spacings, but in a challenging year, narrow rows likely canopied earlier and captured more sunlight, leading to higher yields. Thirty-inch rows, representing 7% of fields, yielded similarly to 15-inch rows, while the remaining 5% of fields were planted in alternative spacings of 18, 20, or 22 inches.

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The major difference in estimated corn yields this year compared to last is shorter cobs. Kernel mass, measured as Thousand Kernel Weight (TKW), will play a key role. A difference between 320 grams and 360 grams TKW could mean as much as a 30-bushel-per-acre swing in yield.

The main difference in soybean yields compared to last year is fewer beans per pod and smaller seed size.

From May 1 to September 6, Crop Heat Unit (CHU) accumulation is about 200 lower than last year, equivalent to roughly 10 days behind in development.

Special thanks to all participating growers and cooperative team members whose efforts made the 16th Great Lakes Grain Crop Assessment Tour a success.

ABOUT GREAT LAKES GRAIN

Great Lakes Grain is one of the largest grain marketing and elevator operators in Ontario, serving farmers across Southwestern and Eastern Ontario. With a commitment to innovation, sustainability, and farmer support, Great Lakes Grain continues to play a vital role in advancing the agricultural industry in the region. 

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