Field work has progressed quickly in the last week and a half. Soil temperatures are still cool, resulting in slow crop emergence.
Cereals
Sulphur deficiencies continue to be reported in winter wheat. Options to correct this deficiency include streaming on liquid ammonium sulphate, (ATS) cut with water, or spreading dry ammonium sulphate. Be aware of differences between sulphur sources. Sulphur in manure is in the elemental form and is only slowly available as it mineralizes. The demand or need for sulphur in winter wheat often occurs prior to sulphur from manure being available. Crops relying on manure for their sulphur needs may still respond to an application of fertilizer with sulphur in a sulphate form. It is also important to note that the sulphur content of fertilizer can be expressed in different ways. Lab analysis of products can be misleading, since some are reporting percent sulphur, and some are reporting percent sulphate (SO42-). For those reporting sulphate, the actual sulphur content is one third of the number on the analysis.
When applying plant growth regulators (PGRs), cold temperatures after application are a bigger concern than hot ones. Cold temperatures can impact wheat growth and development which may influence the effectiveness of PGRs or lead to unexpected stunting or reduced yield. The risk for negative impacts during cold temperatures is also greater when tank-mixing with two or more products.
Stripe rust and leaf rust have been found in Perth and Grey counties. Powdery mildew is also at medium to high pressure in fields across the province, particularly where stands are dense or the variety being grown is susceptible. Variety susceptibility scores can be found under the performance trial results at GoCrops.ca by using the Ontario Cereal Crop Committee head to head feature. Fungicide application may be warranted prior to T3 (heading) on a susceptible variety if powdery mildew infection is spreading to the flag leaf. When pushing N rates, there can be an advantage to splitting fungicide into two passes; this will optimize coverage of leaves as they emerge.
Forages
Winter cereal forage harvest is underway. Triticale has started in the southwestern parts of the province, while rye is anticipated to come off starting the Victoria Day weekend in the east.
More reports than normal are coming in about thin pastures. In some cases, this may be due to snow mould. Overseeding is most likely to be successful if the established stand is cut or grazed short, and the seed is drilled in with a no-till drill or sod-seeder. Packer-seeders (e.g. Brillion) or broadcasting and packing cannot achieve good seed-to-soil contact because the established plants hold the packer above the soil surface. Grazing when pastures are 30-40 cm (12-16 inches) tall will encourage the plants to tiller and help thicken the stand. Leave about 10 cm (4 inches) of residual behind to enable quick regrowth.
Canola
Some growers are prioritizing planting spring canola earlier to get it to flower earlier and avoid extreme summer heat during flowering. Temperatures have been warm enough for flea beetles to start flying. When the temperatures cool later this week, growers are encouraged to monitor canola stems. Flea beetles stop flying in cool weather, but their feeding shifts to stems, which causes more serious crop damage.
Winter canola in areas north of Guelph and in Eastern Ontario is just beginning to flower, while winter canola in southern counties is in late bloom stages. Fungicide application for white mould should be timed for 15 to 20 flowers on the main stem, when flower petals begin to drop. Protecting flower petals with fungicide prevents white mould establishment on plants where infected flower petals fall and land on leaves and stems. Scout for cabbage seedpod weevil prior to fungicide application. More information on white mould and cabbage seedpod weevil can be found on Field Crop News.
Order winter canola seed by June 15 for seeding in 2025 to guarantee seed for this year’s planting.
Corn
Planting has progressed quickly over the last week where soils are fit. Lighter soils in the southwestern parts of the province are as much as 90% planted. Heavy soils across the province, especially in areas that received more rain, have yet to start planting, though tillage for seedbed preparation has just begun in some clay regions.
Soybeans
Estimates suggest as much as a third of the province’s soybean crop has been planted so far.
Volunteer ‘PowerCore Enlist’ corn in soybean fields is not controlled by quizalofop (e.g., Assure II). Use clethodim (e.g., Select) before the 6-leaf stage for effective control. Do not tank-mix clethodim with 2,4-D or dicamba, as this reduces its effectiveness—apply separately.
Weed Control
In corn and soybean fields with waterhemp, always use a two-pass herbicide program: start with an effective pre-emergence herbicide, followed by a post-emergence herbicide that targets small waterhemp seedlings (around 5 cm or ~2 inches).
Agricorp
The federal and provincial governments have extended the deadline for new and existing AgriStability customers to secure 2025 coverage to July 31, 2025. Please refer to the website at www.agricorp.com for current information.
Breakfast Meeting Notes
Ridgetown (May 13th)
- Corn planting progress is estimated at 70 to 80% complete across the region. Heavier ground has not been dry enough to plant. Emergence has been slow, with some fields taking 2 weeks to come up. Some early-planted fields have begun replanting.
- Estimates are that 20 to 25% of the soybean crop is planted. A few fields on clay soils in Lambton County are already replanting. These fields haven’t crusted, but the seed seems to have run out of vigour.
- Earliest winter wheat has the flag leaf emerged. Sulphur deficiencies are still visible in many fields. Some growers missed the application window for herbicide and are forced to skip it.
- Winter barley in Perth County is showing symptoms of barley yellow dwarf virus.
- Triticale (forage) harvest is underway.
- Winter canola has started flowering.
Cobourg (May 13th)
- There was a light frost overnight on Thursday, May 8th, but corn and beans had not yet emerged. Cereals do not seem to have been injured.
- Most winter wheat looks excellent. Some damage reports came in from heavy, poor draining soil near Lake Simcoe. Nitrogen has been applied a second time to some fields, mostly by growers determined not to miss the application window. Powdery mildew has been found.
- Hay and pasture fields are in variable condition. Some look excellent, while others need rejuvenation or termination.
- Corn planting is up to 65% complete. Less has been done east of Brighton, where they have had more rain in the past two weeks.
- Soybean planting progress is estimated at around 30%.
Arnprior (May 13th)
- Winter wheat is around GS 30-31. Some early herbicide passes are going on, but many growers are waiting for early next week to add fungicide or PGRs. Very low diseases pressures in the area – wheat is clean and green.
- Planting deadline for spring wheat in Area B is May 15th
- For winter canola, most acres in the region look good. Spring canola acres are expected to be consistent with past years.
- Fall rye (forage) harvest is anticipated to start Victoria Day weekend.
- Alfalfa is progressing well, although stem counts in many fields are a little below target for full yield potential. Fungicide has been applied to some fields.
- Corn planting progress is estimated at 25 to 30% across the region, with pockets as high as 50% and others not yet started. Some pre-emerge herbicides followed the corn planter, and some of these were applied with UAN.
- Soybean planting is around 5 to 25% complete. Nothing has emerged yet, but it has been cool.
Mount Forest (May 14th)
- Earliest planted wheat (e.g. September) is getting close to flag leaf emergence while late-planted wheat is closer to growth stage 32 (2nd node). Many fields are still in the T1 fungicide application window.
- Except for pockets of heavier soils or heavier rains where corn planting just started over the past week (parts of Grey, Simcoe counties), most attendees reported corn to be 90+% planted. Early planted corn (e.g. last week of April) is now emerging, stands look good at this point, though emergence is slower than last year
- Soybean planting progress reports range, but are approximately 50% done. Overall, progress is well ahead of 2024.
- Earlier planted winter canola is expected to reach full bloom this week, later planted winter canola is just starting to bloom.
- Purple deadnettle is posing a challenge in some fields in Bruce County. More information on controlling this weed can be found here.
- Scentless chamomile has a large germination period and requires control efforts in spring and fall. More information on controlling this weed can be found here.
- Significant bee mortality this winter, early break of dormancy in March is suspected to be part of the issue this year. Some apiaries have lost 100% of their hives.
Northern Ontario (May 14th)
- The weather in the north was cool and wet until this past weekend. Daytime high temperatures since have been in the mid to high 20°Cs, and field work is finally underway. Cooler conditions are in the forecast for later this week, with possible snow in Cochrane and Temiskaming districts.
- There are already several forest fires burning in Rainy River and Kenora districts.
- Well-drained and tile drained fields are being worked and planted across the north. Untiled fields will be ready to be worked very soon where dry weather holds.
- Nitrogen is going out on winter cereals on Manitoulin. Fall rye and winter triticale were affected by snow mould in some parts of the north. Scouting is important to determine the extent of the damage and make decisions around keeping the stand.
- A couple of fields of corn (sweet and field) have been planted under plastic mulch in Cochrane and Nipissing districts.
- Warm temperatures this week mean flea beetles are already active.
- May 31st is Agricorp’s deadline to plant spring cereals, soybeans, and corn in Area E. Please refer to the website at www.agricorp.com for current information.
OMAFA Weather Summary: Thurs May 8—Wed May 14, 2025
| Location | Highest Temp (°C) | Lowest Temp (°C) | Rain for Week (mm) | Rain Since April 1st (mm) | GDD0C April 1st | GDD5C April 1st | CHU May 1st |
| HARROW | |||||||
| 2025 | 24.1 | 1.8 | 28.5 | 172.4 | 439 | 241 | 108 |
| 2024 | 26.8 | 6.3 | 15.3 | 152.0 | 535 | 313 | 114 |
| 2023 | 25.6 | 4.9 | 0.2 | 64.3 | 452 | 243 | 121 |
| 10 YR Norm (2011-2020) | 19.6 | 6.8 | 20.5 | 135.5 | 405 | 187 | 92 |
| RIDGETOWN | |||||||
| 2025 | 24.8 | -0.9 | 1.5 | 104.0 | 408 | 213 | 97 |
| 2024 | 25.9 | 7.1 | 9.0 | 143.3 | 492 | 274 | 110 |
| 2023 | 26.4 | 3.2 | 0.2 | 114.1 | 424 | 224 | 114 |
| 10 YR Norm (2011-2020) | 19.5 | 5.2 | 18.1 | 116.4 | 362 | 150 | 82 |
| SARNIA | |||||||
| 2025 | 25.7 | 2.5 | 1.6 | 151.5 | 392 | 203 | 90 |
| 2024 | 27.9 | 7.0 | 11.3 | 111.1 | 474 | 259 | 93 |
| 2023 | 26.4 | 3.1 | 0.0 | 106.0 | 417 | 217 | 90 |
| 10 YR Norm (2011-2020) | 19.3 | 4.7 | 17.2 | 116.2 | 344 | 133 | 75 |
| LONDON | |||||||
| 2025 | 26.7 | 1.3 | 4.1 | 143.1 | 395 | 211 | 108 |
| 2024 | 25.6 | 6.3 | 13.8 | 135.5 | 485 | 264 | 100 |
| 2023 | 27.5 | 4.6 | 0.0 | 150.4 | 417 | 218 | 116 |
| 10 YR Norm (2011-2020) | 19.9 | 5.5 | 14.6 | 121.9 | 354 | 145 | 84 |
| BRANTFORD | |||||||
| 2025 | 27.3 | 1.1 | 2.5 | 133.1 | 394 | 207 | 100 |
| 2024 | 24.3 | 4.9 | 9.5 | 101.1 | 448 | 232 | 96 |
| 2023 | 27.9 | 2.9 | 0.0 | 120.0 | 403 | 201 | 111 |
| 10 YR Norm (2011-2020) | 18.8 | 3.0 | 15.3 | 134.6 | 327 | 122 | 69 |
| WELLAND | |||||||
| 2025 | 27.7 | 1.7 | 0.0 | 83.8 | 401 | 210 | 93 |
| 2024 | 24.8 | 5.6 | 6.2 | 123.4 | 479 | 260 | 106 |
| 2023 | 25.7 | 3.1 | 0.0 | 116.1 | 415 | 208 | 104 |
| 10 YR Norm (2011-2020) | 20.4 | 5.6 | 25.5 | 139.4 | 358 | 148 | 84 |
| GODERICH | |||||||
| 2025 | 25.2 | -1.9 | 0.0 | 90.9 | 349 | 169 | 85 |
| 2024 | 24.7 | 4.2 | 25.1 | 118.9 | 416 | 208 | 76 |
| 2023 | 23.7 | 2.5 | 0.0 | 85.4 | 371 | 187 | 101 |
| 10 YR Norm (2011-2020) | 16.9 | 3.9 | 19.5 | 107.3 | 298 | 98 | 61 |
| ELORA | |||||||
| 2025 | 26.0 | -0.4 | 2.6 | 128.1 | 349 | 173 | 93 |
| 2024 | 22.8 | 3.5 | 7.6 | 127.6 | 391 | 185 | 78 |
| 2023 | 26.0 | 1.5 | 0.0 | 106.5 | 358 | 174 | 102 |
| 10 YR Norm (2011-2020) | 18.7 | 3.3 | 17.3 | 129.0 | 289 | 93 | 64 |
| MOUNT FOREST | |||||||
| 2025 | 27.1 | 0.1 | 0.6 | 99.3 | 348 | 174 | 97 |
| 2024 | 23.0 | 4.3 | 14.7 | 144.3 | 387 | 184 | 73 |
| 2023 | 25.4 | 2.5 | 0.0 | 134.2 | 358 | 178 | 98 |
| 10 YR Norm (2011-2020) | 18.3 | 3.9 | 14.3 | 113.5 | 278 | 90 | 65 |
| BARRIE | |||||||
| 2025 | 26.8 | 1.0 | 0.9 | 96.3 | 319 | 147 | 92 |
| 2024 | 22.6 | 1.8 | 16.0 | 215.5 | 366 | 162 | 82 |
| 2023 | 25.8 | 2.0 | 0.0 | 120.6 | 354 | 168 | 97 |
| 10 YR Norm (2011-2020) | 18.0 | 3.0 | 14.7 | 114.2 | 267 | 83 | 64 |
| PETERBOROUGH | |||||||
| 2025 | 27.2 | -0.6 | 0.7 | 106.3 | 353 | 172 | 97 |
| 2024 | 19.5 | 3.0 | 15.8 | 168.5 | 392 | 184 | 86 |
| 2023 | 26.9 | 1.1 | 0.0 | 105.3 | 383 | 187 | 100 |
| 10 YR Norm (2011-2020) | 18.9 | 2.9 | 17.2 | 118.2 | 301 | 104 | 73 |
| KEMPTVILLE | |||||||
| 2025 | 28.1 | 2.2 | 0.6 | 107.7 | 366 | 182 | 90 |
| 2024 | 19.7 | 4.0 | 23.5 | 163.2 | 399 | 191 | 88 |
| 2023 | 25.9 | 1.4 | 0.3 | 175.6 | 401 | 209 | 100 |
| 10 YR Norm (2011-2020) | 19.1 | 4.5 | 17.9 | 126.7 | 318 | 123 | 76 |
| SUDBURY | |||||||
| 2025 | 28.8 | -1.5 | 1.1 | 91.9 | 235 | 96 | 92 |
| 2024 | 23.1 | 2.0 | 11.4 | 212.3 | 296 | 118 | 65 |
| 2023 | 24.9 | -0.9 | 12.9 | 163.0 | 275 | 130 | 95 |
| 10 YR Norm (2011-2020) | 17.4 | 1.8 | 18.1 | 116.7 | 190 | 55 | 53 |
| EARLTON | |||||||
| 2025 | 30.1 | -3.5 | 1.9 | 82.1 | 198 | 75 | 77 |
| 2024 | 22.4 | 2.2 | 1.1 | 162.4 | 288 | 116 | 78 |
| 2023 | 25.7 | 0.2 | 2.5 | 118.7 | 270 | 121 | 85 |
| 10 YR Norm (2011-2020) | 16.9 | 0.5 | 12.5 | 90.3 | 159 | 47 | 49 |
| SAULT STE MARIE | |||||||
| 2025 | 27.6 | -2.8 | 0.4 | 109.8 | 233 | 86 | 75 |
| 2024 | 17.6 | 0.7 | 7.1 | 175.6 | 296 | 103 | 50 |
| 2023 | 25.8 | 1.7 | 0.3 | 122.2 | 270 | 124 | 90 |
| 10 YR Norm (2011-2020) | 15.8 | 0.2 | 15.4 | 109.3 | 170 | 37 | 37 |
| THUNDER BAY | |||||||
| 2025 | 28.7 | -5.4 | 0.7 | 113.0 | 186 | 61 | 83 |
| 2024 | 23.8 | -2.6 | 1.2 | 77.9 | 242 | 73 | 64 |
| 2023 | 27.5 | -0.3 | 1.1 | 91.5 | 192 | 70 | 87 |
| 10 YR Norm (2011-2020) | 15.6 | -0.9 | 11.6 | 71.2 | 152 | 28 | 39 |
| FORT FRANCES | |||||||
| 2025 | 34.1 | 0.6 | 0.0 | 71.0 | 302 | 149 | 139 |
| 2024 | 23.3 | -0.6 | 7.2 | 62.5 | 265 | 86 | 79 |
| 2023 | 25.2 | 3.2 | 37.3 | 92.8 | 243 | 114 | 109 |
| 10 YR Norm (2011-2020) | 17.6 | -0.4 | 15.3 | 67.3 | 186 | 44 | 48 |
This weather summary is compiled by OMAFA using Environment Canada weather station data provided by Agriculture and Agri-Food Canada. Data quality is verified but accuracy is not guaranteed and should be used for general information purposes only. For additional locations and weather analysis, visit the OMAFA Pest and Weather System (PAWS)