The start of this week has been marked by several days of well above normal temperatures – daily highs in the low to mid 30’s brings the first summer-like hot spell across much of Ontario. These temperatures have helped reduce the heat unit deficit that has been a hallmark of spring 2025.
Field Corn
Very warm temperatures this week have resulted in rapid growth of corn, welcome in a spring behind normal in heat units. Early planted fields (e.g. April, early May) have now just closed rows and would be in the V8 stage or more. Sidedressing in a lot of these fields has now wrapped up but continues in areas with later planted corn (Image 1). This is a good time to scout fields – some nutrient deficiencies (Mg, Zn, Mn) and compaction are becoming more visible at this stage. Heat or moisture stress has started to show up during the heat of the day on some lighter soils or knolls in areas that have received little recent rainfall. Yield impacts of moisture stress are minimal at this stage. Tarspot has been confirmed in NW Indiana – pay attention for Tarspot observations in Ontario. See Crop Protection Network: https://cropprotectionnetwork.org/ for disease forecasting tools.
Some growers and retailers are now readying for late nitrogen (N) applications (e.g. topdress or drop hose applications). Besides avoiding N losses, another advantage of later N applications is the ability to adjust rates in-season. Research by Dr. Bill Deen and Caleb Niemeyer at the University of Guelph Elora Research Station has shown year-to-year optimum corn N rates to be well related to yield. At Elora, yields were highly correlated to rainfall received from the mid-June to mid-July timeframe. Thus, optimum N rates were well related to rainfall from mid-June to mid-July as well – the more rainfall during this period, the higher the yields and the higher the optimum N rate. In environments with more N loss potential (heavier or poorly drained soils, very well drained sands), this relationship might not be as clear. Consider N rate adjustments or N-rate strips to fine tune N strategies.
Soybeans
There has still been some talk about variability or lower than expected soybean stands. General minimum populations to expect 100% of crop yield (assuming even stand) are 90,000 plants/acre on lighter textured soils and 110,000 plants/acre on heavier textured soils.
Heat has been welcome to get the soybean crop growing. Many fields are still reported to have a yellowish hue, and in many cases, this is likely just from nodulation that has not started producing nitrogen yet. This should go away as nodulation progresses. Early planted soybeans (e.g. late April) are reported to have just started flowering this week.
Soybean aphids have been reported in some fields. Hot temperatures should limit population increases. Most fields are still well below threshold (250 aphids per plant on 80% of plants and increasing, R1 to R5 stages) and action is not warranted. Natural predator populations are strong from feeding on aphids in cereal crops and should also help slow population growth. It is important to scout and watch progress.
Cereals
As grain fill continues in winter wheat, many fields are now starting to turn colour (Image 2). While the heat has been welcome for most crops, well above normal temperatures received this week could shorten the grain-fill period of winter wheat which could impact yield potential. Winter barley harvest is expected to begin in the south next week.
Between tolerant varieties and fungicides with good efficacy, stripe rust has generally been well managed across the province. In cases where susceptible varieties were grown and did not receive a fungicide application (or received one too late) there was potential for significant loss of leaf area. Growers should consider variety tolerances when selecting seed for this fall.
Edible beans
Most edible bean fields are reported to look good. Main concerns around stands are for fields planted very early (e.g. late May) or those that were planted recently in areas that received heavy rains.
Canola
Winter canola is in the grain fill/ripening stage. Spring canola generally looks good in most of the spring canola growing regions. Emergence has been reported to be good, and the crop has generally progressed beyond issues like frost and flea beetles. Some crop is just starting to bolt – most weed control should have happened by this stage. There are some concerns about Swede Midge populations in some areas of the north where there are high canola acres and short canola rotations.
Forages
This past week has presented a reasonable opportunity for hay production. High humidity and some thunderstorms have created challenges for making dry hay for some. Haylage and baleage has been coming along well. Rain would be welcome for regrowth for second cut, but regrowth appears to be coming along well in most areas. Leafhoppers have been reported in some areas – growers should be monitoring for pressure.
Breakfast Meeting Notes
Ridgetown Ag Breakfast meeting notes – June 24, 2025
Wheat
- Hot days and warm nights as of late have likely reduced grain fill period and thereby yield potential
- Estimated 31 days of grain fill now, compared to 34 days estimated last week
- Reduction in grain fill time equates to roughly 4 bu/ac loss per day
- Plants under higher stress to begin with from dry conditions, stripe rust, etc. are less tolerant of heat stress now
- Drastic differences between varieties in terms of tolerance to stripe rust reported at unsprayed Elora performance trials
- One variety noted as being almost completely void of green material
- Trials from Syngenta noted that a 3 day delay in application of T3 fungicide following stripe rust infection led to a 15% reduction in green leaf area
- Reports of high fusarium infection in SW Ohio as harvest begins
- Models show lower risk closer to the Great Lakes
- Agronomists stress to make a harvest plan:
- Start harvest at 18% moisture, even if straw is still green
- Early harvest is best way to harvest high quality grain and avoid sprouts
Corn
- Rapid growth since warm temperatures arrived, in some fields unevenness is more pronounced now
- Lots of sidedressing occurring in fields
- Some logistical problems with UAN earlier in spring, but supply is good overall
- Rains have pushed back some topdressing of urea later than planned
- May be some injury from urea in the whorl, but mainly cosmetic
- Reports of anhydrous ammonia being applied 8” below the surface and still getting some leaf injury
- Soil below 2” is very compact in some areas
- Reports of fertilizer burn on sandy knolls
- Injury showing on roots, likely from higher rates of N, K, S, Mg combined with cool, dry spring preventing downward movement of salts away from rooting area
- Mg, Zn, Mn deficiency appearing
- Tar spot has been confirmed in NW Indiana, spore traps are set to identify disease when it comes to Ontario
- See Crop Protection Network: https://cropprotectionnetwork.org/ for disease forecasting tools
Soybeans
- Yellowish colouring in many fields as nodulation is just starting to occur
- Reduced stands noted on headlands in many fields in the area
- Some unevenness in stands noted as a result of residue management of corn stalks, especially where moved from ponding
- Soybean aphids (SBA) have been located in fields in northern Oxford and northern Perth counties at increasing populations.
- Temperatures above 34C halt SBA reproduction so populations likely won’t increase rapidly. Scout early planted fields that are close to entering R1 first. During R1 to R5 stage of soybeans, an insecticide application is only required once 80% of the plants in the field have at least 250 aphids per plant and it is apparent that the population is on the increase.
- Natural enemy populations are abundant this year from feeding on cereal aphids, so make sure to take note of their presence and abundance before making a management decision.
- More information on soybean aphids can be found on CropIPM.
Edible Beans
- Latest planted beans having some emergence issues if not up prior to heavy rains
- Replants on hold waiting for drier conditions and may depend on upcoming forecast
Crop Protection
- Waterhemp population is spreading
- Proper identification is critical, and plan is necessary
- “Waterhemp makes fleabane control look easy”
- Updates to corn fungicide labels:
- Delaro Complete: highest labelled rate increased to 880 mL/ha for suppression of fusarium and gibberella ear rots
- Non-ionic surfactant can be added, but only after tassel emergence
- Miravis Neo: label now lists control of tar spot
- Delaro Complete: highest labelled rate increased to 880 mL/ha for suppression of fusarium and gibberella ear rots
- Discussion around issue of arrested ear development or “beer-can corn” syndrome which can be caused by application of non-ionic surfactants prior to tassel emergence
- Purdue extension article: https://www.extension.purdue.edu/extmedia/BP/BP-85-W.pdf
- Fungicide efficacy information located at:
- Crop Protection Hub: https://cropprotectionhub.omafra.gov.on.ca/
- Crop Protection Network: https://cropprotectionnetwork.org/
Arnprior Ag Breakfast meeting notes – June 24, 2025
Winter Cereals
- T3’s are done, not all of the winter wheat is at grain filling quite yet.
- Standing well despite severe storms going through over the weekend
- Stands are uniform and look good.
- Canopies aren’t super thick, just average, but PGRs are holding and doing their job
- Low stripe rust pressures, but growers are cautious about potential for stripe rust moving into the spring wheat.
- There is some discussion around acres that will be baled for straw versus blown back on the field at harvest.
Spring Cereals
- Most of it has reached flag leaf the last couple of days.
- Overall, spring wheat looks good, and stands are fairly even.
- Range of stages depending on geography – planting dates varied greatly this spring.
- Canopies are coming to head, potential for stripe rust to come into spring wheat in the coming weeks. Fungicide applications at pollination will be critical.
- With hot, drier weather, fungicide may be a game time decision but consideration should be given to an application with the concerns over stripe rust movement.
Canola
- Spring canola planting window was quite large – early May through early June
- Lots of it is starting to bolt, so the weed control window is shrinking rapidly.
- No winter canola left in the region – between winterkill and hail, there are very few acres left to harvest.
- Expecting lower winter canola acres this fall in parts of Ottawa-Carleton and Renfrew.
Forages
- Yields for first cut have been variable. Mostly believed to be a function of fertility and age of the stand.
- Second cut needs some more rain to keep going, but is coming in nicely.
- New seedings are coming, but a bit slowly. Some stands are a little thin. Can top up next spring, but has to be done early to avoid autotoxicity (some like the frost seeding option, but this can be risky as alfalfa is very sensitive to frost from second trifoliate until crown development finishes – very early planting could increase risks of new alfalfa being killed by a spring frost), grass or red clover are alternative options
- Some weevil damage in the area, not heavy pressures.
- Some reported leafhoppers to the south, winds will likely move them along over the next couple weeks.
Corn
- Staging is all over the map; 4 leaf to knee high already
- Wind has tipped some of the corn on a slant the last couple of days.
- Lot of sidedress has been done, but still a bit to finish up.
- Seeing some planting sins with fields that were a little wet when planted – roots are a bit constricted, etc. seeing differences in staging/plant size based on this as fields get drier
- Pre-emerge herbicides are holding well, as are most of the early post-emerge applications.
- Seeing lots of tillers on the corn, usually a good sign that corn is coming along well.
- Populations aren’t as high as we’d like to see – some gaps in fields, seed just didn’t come through. Can see where fields were planted when they should’ve waited just a bit. Cool nighttime temperatures are likely a big factor.
Soybeans
- April planted beans are starting to flower – April 28th planted, shorter season variety.
- A few replants for early planted beans, seedbed was good, but cool, damp weather is suspected to have caused injury. Suspected due to the ground just got hard; rains were cold, high and low temperatures were quite cool.
- Lot of yellow in the no-till beans, thinner stands. Its typical to see lower populations early on, but numbers are a little lower than growers would like to see.
- Seeing high erosion in soybeans fields that got fall tillage. Beans in those fields look the best right now, but soil movement this winter/spring was concerning.
Weed Control
- Stay away from heat of the day applications with this hot weather, and try to increase the water volume a bit.
- These warm temperatures are prime weather for liberty/glufosinate applications, but keep water volumes at 20gal/ac.
- Some beans showing some injury/looking tough for a couple days with herbicide applications. Suspected to be because of increased metabolism at the time of application. Most have come out of it well and there are little concerns at this point.
Cobourg Ag Breakfast meeting notes – June 24, 2025
- Pockets of heavy soil between Belleville and Kingston are still struggling to get fields planted ahead of Agricorp deadlines due to wet conditions.
- Knolls and free-draining fields in Kawartha Lakes, Durham, and Northumberland are starting to show minor signs of moisture stress and could use some rain.
Cereals
- Overall, the wheat crop looks excellent.
Forages
- No alfalfa weevil was reported in this part of the province this year. Potato leafhoppers are appearing in fields, and growers should be scouting for them. While haylage and baleage harvest has been progressing well, it has been a struggle to make dry hay. The only long windows in the forecast without rain had days of very high humidity where the crop couldn’t dry. Regrowth on fields cut early is coming along well.
Corn
- The earliest-planted corn is around the 6-leaf stage. Fields planted in June are up to 3- to 4-leaf stage. Most of the crop in the area is anticipated to be about knee high by July 1st. Corn planted over the Victoria Day weekend seems to still be struggling, since cool weather persisted for so long after planting.
Soybeans
- A lot of acres originally intended for corn have been switched to soybeans. Wet and windy weather all spring has limited the available days for spraying. As a result, there are a lot of weedy soybean fields. Challenges with cool soils and crusting on clays has reduced emergence, so many fields are being replanted.
Northern Ag Breakfast meeting notes – June 25, 2025
Relief from the dry conditions have come over the past weekend with rains across the north. Some warmth has come as of late, helping the crop to catch up somewhat after a late start with the cool spring. Overall, crop conditions look pretty good.
Horst Bohner, Soybean Specialist with OMAFA gave an update on soybeans, and some of the issues facing the crop with the cool start to the year:
- Cool spring has led to delayed emergence, with some crop taking 4-5 weeks to emerge
- Reduced vigour has led to thin stands, especially in no-till fields or with heavy surface residue
- General minimum populations to expect 100% of crop yield (assuming even stand):
- 90,000 plants/acre on lighter textured soils
- 110,000 plants/acre on heavier textured soils
- Data from Elora shows that adapted maturity varieties outyield “long” and “short” maturity varieties for the individual area
- Switching to earlier maturing variety should occur at the crop insurance deadline
- Some data from US states shows response to N and S when dealing with heavy residue – up to 100 lb/ac ammonium sulphate may show response on light, sandy soils with early planted soybeans
- Seed corn maggot among other insect pests isn’t very well controlled with insecticide-treated seed, especially in conditions with slow emergence
- But still offers suppression in fields with high pest populations
- Nodulation may be slowed when conditions stay below 10°C
Rainy River
- Good conditions overall, wheat is headed out now
- Flea beetle trouble earlier in the spring now looks to be under control
Algoma
- Warm weather has helped seeding finish up
- As of a week ago, still plenty of unseeded fields
Cochrane
- Very wet now after heavy rains
- Emergence of canola, oats, and soybeans still strong
- Have had up to 4 incidents of frost, up to June 19 with some damage reported
Timiskaming
- Some concern with Swede Midge populations in canola grown under tight rotations in Earlton area
- July 17th – New Liskeard Diagnostic Days
Nipissing
- Canola and wheat look good, but growing slow to this point
- Concerns of Barley Yellow Dwarf Virus present with high levels of infection in some fields
- Earliest planted fields are most affected, with later planted fields almost unaffected
Mt. Forest Ag Breakfast meeting notes – June 25, 2025
Corn
- Corn has changed significantly with the heat the last couple weeks
- Corn generally looks very good, early planted fields (e.g. late April, early May) now closing rows (V8 or more advanced)
- Traditional sidedressing (e.g. V6 stage) has generally wrapped up
- Applicators are now getting ready for later N applications (topdress or drop hose applications)
- With recent heat, some heat or moisture stress has been evident on knolls or lighter areas of fields during the heat of the day, rain would be welcome in most areas
Soybeans
- Growth has seemed very slow
- Early planted soybeans now flowering
- Replants generally very low, except where planted prior to heavy rains
- Aphid numbers have started to build in some fields, but still well below thresholds, no actions needed at this time
Wheat
- Most wheat looks good, stripe rust has been held back where tolerant variety or fungicide was applied (as long as not applied too late)
- Hot weather may shorten grain fill, reduce some yield potential
Edible Beans
- Edible beans generally look very good, except for very early planted fields (e.g. late May) where some stands are a little tough
Weed Control
- Weed control in corn and soybeans generally looks very good, excellent pre-emerge herbicide activity this spring, some weeds just starting to break through in fields where herbicides have been long applied
- While herbicide activity has been good, there are still some very weedy fields out there this year – late applications, no applications, real yield loss
Events
- AgSpray Expo – July 23rd, Jasper, ON – register at eocac.ca
- New Liskeard Diagnostic Day – July 17th – register here
OMAFA Weather Summary: Thurs June 19—Wed June 25, 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 | 34.3 | 15.8 | 8.4 | 284.2 | 1189 | 781 | 215 |
| 2024 | 32.7 | 17.3 | 14.0 | 220.8 | 1389 | 957 | 211 |
| 2023 | 28.1 | 12.5 | 15.6 | 154.1 | 1175 | 756 | 188 |
| 10 YR Norm (2011-2020) | 26.8 | 15.1 | 25.3 | 262.1 | 1193 | 765 | 186 |
| RIDGETOWN | |||||||
| 2025 | 33.8 | 15.3 | 10.2 | 207.7 | 1127 | 721 | 206 |
| 2024 | 33.0 | 15.9 | 25.4 | 279.0 | 1303 | 875 | 203 |
| 2023 | 28.4 | 8.5 | 7.1 | 186.1 | 1109 | 698 | 180 |
| 10 YR Norm (2011-2020) | 26.2 | 14.2 | 14.6 | 220.6 | 1109 | 687 | 176 |
| SARNIA | |||||||
| 2025 | 34.6 | 15.7 | 7.7 | 236.5 | 1075 | 675 | 201 |
| 2024 | 33.6 | 15.2 | 9.9 | 204.3 | 1278 | 854 | 197 |
| 2023 | 28.9 | 9.9 | 16.0 | 175.4 | 1064 | 654 | 170 |
| 10 YR Norm (2011-2020) | 26.2 | 13.3 | 31.8 | 248.8 | 1064 | 644 | 172 |
| LONDON | |||||||
| 2025 | 34.0 | 14.3 | 2.5 | 234.6 | 1054 | 670 | 154 |
| 2024 | 32.9 | 14.7 | 29.4 | 269.4 | 1281 | 850 | 198 |
| 2023 | 28.4 | 11.0 | 18.5 | 245.6 | 1112 | 702 | 179 |
| 10 YR Norm (2011-2020) | 26.4 | 13.8 | 28.1 | 250.4 | 1090 | 671 | 173 |
| BRANTFORD | |||||||
| 2025 | 33.7 | 14.5 | 2.6 | 253.6 | 1085 | 693 | 174 |
| 2024 | 32.2 | 14.4 | 10.1 | 216.9 | 1225 | 799 | 197 |
| 2023 | 28.7 | 12.3 | 3.1 | 186.8 | 1099 | 688 | 179 |
| 10 YR Norm (2011-2020) | 26.5 | 12.2 | 17.0 | 235.2 | 1071 | 656 | 167 |
| WELLAND | |||||||
| 2025 | 34.2 | 15.6 | 6.6 | 150.2 | 1124 | 723 | 206 |
| 2024 | 31.1 | 14.6 | 34.5 | 271.7 | 1273 | 844 | 203 |
| 2023 | 28.9 | 10.1 | 9.0 | 179.6 | 1101 | 684 | 185 |
| 10 YR Norm (2011-2020) | 26.2 | 13.9 | 19.4 | 248.0 | 1091 | 671 | 174 |
| GODERICH | |||||||
| 2025 | 31.7 | 13.1 | 10.7 | 166.8 | 1015 | 624 | 191 |
| 2024 | 30.2 | 13.1 | 11.9 | 197.7 | 1145 | 727 | 190 |
| 2023 | 30.2 | 10.9 | 10.0 | 138.5 | 994 | 601 | 177 |
| 10 YR Norm (2011-2020) | 24.7 | 13.1 | 23.8 | 219.4 | 969 | 559 | 164 |
| ELORA | |||||||
| 2025 | 33.7 | 14.1 | 3.2 | 205.5 | 989 | 608 | 180 |
| 2024 | 32.9 | 12.6 | 49.5 | 250.5 | 1137 | 721 | 189 |
| 2023 | 27.3 | 11.2 | 8.7 | 162.7 | 1008 | 614 | 173 |
| 10 YR Norm (2011-2020) | 25.1 | 12.3 | 25.4 | 245.9 | 963 | 557 | 158 |
| MOUNT FOREST | |||||||
| 2025 | 32.9 | 14.0 | 7.8 | 186.7 | 983 | 605 | 165 |
| 2024 | 30.9 | 14.3 | 12.5 | 237.7 | 1124 | 711 | 194 |
| 2023 | 27.8 | 12.5 | 31.9 | 211.2 | 1007 | 618 | 179 |
| 10 YR Norm (2011-2020) | 24.8 | 12.6 | 38.1 | 248.4 | 946 | 548 | 157 |
| BARRIE | |||||||
| 2025 | 34.3 | 11.6 | 13.9 | 196.2 | 978 | 597 | 188 |
| 2024 | 32.7 | 12.0 | 69.7 | 374.7 | 1080 | 667 | 185 |
| 2023 | 27.5 | 8.8 | 14.8 | 226.4 | 987 | 592 | 167 |
| 10 YR Norm (2011-2020) | 24.9 | 11.0 | 23.3 | 235.1 | 922 | 528 | 151 |
| PETERBOROUGH | |||||||
| 2025 | 33.4 | 9.7 | 2.5 | 198.0 | 1017 | 626 | 189 |
| 2024 | 32.8 | 9.8 | 32.3 | 267.2 | 1107 | 689 | 183 |
| 2023 | 28.5 | 8.5 | 7.6 | 191.1 | 1014 | 608 | 164 |
| 10 YR Norm (2011-2020) | 25.8 | 10.7 | 18.6 | 233.9 | 975 | 569 | 154 |
| KEMPTVILLE | |||||||
| 2025 | 34.1 | 9.9 | 27.1 | 180.8 | 1070 | 676 | 189 |
| 2024 | 32.4 | 13.6 | 35.2 | 287.7 | 1168 | 750 | 187 |
| 2023 | 28.7 | 9.6 | 26.1 | 243.5 | 1067 | 665 | 172 |
| 10 YR Norm (2011-2020) | 26.3 | 12.2 | 19.8 | 235.8 | 1021 | 616 | 167 |
| SUDBURY | |||||||
| 2025 | 32.5 | 7.4 | 28.5 | 170.9 | 836 | 487 | 160 |
| 2024 | 31.5 | 13.0 | 40.0 | 327.0 | 976 | 588 | 171 |
| 2023 | 29.7 | 10.6 | 33.7 | 283.5 | 914 | 561 | 174 |
| 10 YR Norm (2011-2020) | 24.9 | 10.7 | 20.7 | 218.5 | 824 | 479 | 146 |
| EARLTON | |||||||
| 2025 | 34.3 | 5.8 | 37.1 | 174.1 | 794 | 462 | 155 |
| 2024 | 33.2 | 13.1 | 28.0 | 272.7 | 967 | 586 | 174 |
| 2023 | 31.2 | 9.1 | 0.0 | 193.0 | 901 | 547 | 168 |
| 10 YR Norm (2011-2020) | 24.5 | 9.4 | 20.1 | 199.7 | 755 | 433 | 139 |
| SAULT STE MARIE | |||||||
| 2025 | 30.8 | 8.4 | 25.7 | 191.2 | 798 | 442 | 145 |
| 2024 | 25.8 | 10.8 | 24.5 | 291.8 | 899 | 496 | 146 |
| 2023 | 30.2 | 9.4 | 3.5 | 181.4 | 887 | 531 | 168 |
| 10 YR Norm (2011-2020) | 23.3 | 7.7 | 23.7 | 226.3 | 721 | 378 | 125 |
| THUNDER BAY | |||||||
| 2025 | 28.7 | 6.7 | 15.1 | 188.6 | 707 | 379 | 134 |
| 2024 | 29.0 | 6.9 | 9.1 | 216.9 | 800 | 421 | 134 |
| 2023 | 27.8 | 8.0 | 27.1 | 156.9 | 782 | 450 | 147 |
| 10 YR Norm (2011-2020) | 22.9 | 7.7 | 33.4 | 212.2 | 683 | 350 | 121 |
| FORT FRANCES | |||||||
| 2025 | 28.6 | 5.2 | 66.0 | 189.0 | 878 | 515 | 150 |
| 2024 | 29.1 | 5.9 | 8.7 | 245.6 | 858 | 469 | 137 |
| 2023 | 33.0 | 11.5 | 20.8 | 135.5 | 961 | 622 | 166 |
| 10 YR Norm (2011-2020) | 24.6 | 9.0 | 21.8 | 207.3 | 790 | 438 | 138 |
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)