Crop Conditions – Week of May 22nd, 2023

Wheat leaf with severe Physiological Fleck.


Outside of rains received last Friday and Saturday, conditions have generally been excellent for field work over the past week which has allowed planting to continue or wrap-up at a quick pace for most parts of the province.

Cool night temperatures, including frost warnings in some areas, is expected to have minimal impacts for most field crops overall, but may locally affect some frost-prone areas. This also presents some challenges for application of crop protection products.   


Winter wheat flag leaf is emerging in more advanced areas. No herbicides or plant growth regulators should be applied at flag leaf stage. Heads are or may be emerging over the next week in the most advanced areas (e.g., extreme SW Ontario). Fungicide applications protecting against Fusarium Head Blight (T3) are best timed when anthers start to emerge in the middle of the wheat heads.

In general, foliar disease pressure is low, though Powdery Mildew is showing up in some susceptible varieties. Fields should be scouted, particularly if growing a susceptible variety. Physiological fleck (Figure. 1) has been showing up in some fields, which is not unusual when prolonged periods of cloudy weather are followed by sunshine. Physiological fleck may look like a leaf disease (yellowing blotches on leaves) but can be distinguished from diseases by the lack of fruiting structures (e.g., small black pycnidia spots for Septoria leaf spot).

Figure 1. Wheat leaf with severe Physiological Fleck.

Figure 1. Wheat leaf with severe Physiological Fleck.

Insect pest pressure has generally been lower than normal this growing season. Nutrient deficiencies (e.g., sulfur) have been noted in some fields. This is a good time to diagnose these deficiencies. Yield responses to remediation efforts can still occur.


Corn planting is estimated to be nearly complete in most areas, with many areas having wrapped up last week. Even areas with heavier soils that typically start later are reported to be on the home stretch. Corn planted during the early window in April (week of April 9) started to emerge last week, while corn planted as soon as soil conditions became fit in May (e.g., May 9 or 10) is emerging the beginning of this week. Some planting continues where corn is planted after a forage harvest (e.g., ryelage). Stands for very early planted corn (e.g., April) should be carefully checked. There have been a few reports of replants where stands were not satisfactory. The Replant Decision Aid at may help in replant scenarios.


Soybean planting continues. Some reports of planting completion range from 75% to 90%. Earlier planted soybeans are continuing to emerge this week. Growers evaluating stands should be patient – sometimes it can take a while for all soybeans to germinate and emerge, especially under drier conditions. Table 2-13 provides some guidance for yield potential for various plant stands. Soybean replanting should not be considered unless final stand falls below 100,000 plants per acre. If thickening an existing stand, use the same variety.

Table 2-13: Expected Yield of Soybeans in Optimum and Reduced Stands. Source: Agronomy Guide (Publication 811).

% of Full StandRow SpacingExpected Final Yield as % of Optimum
18 cm (7”)36 cm (14”)53 cm (21”)76 cm (30”
100%553,300 plants/ha (223,900 plants/acre)402,600 plants/ha (162,900 plants/acre)392,700 plants/ha (158,900 plants/acre)405,100 plants/ha (163,900 plants/acre)100%
80%442,100 plants/ha (178,900 plants/acre)323,600 plants/ha (131,000 plants/acre)313,700 plants/ha (127,000 plants/acre)323,600 plants/ha (131,000 plants/acre)100%
60%331,000 plants/ha (134,000 plants/acre)242,100 plants/ha (98,000 plants/acre)237,100 plants/ha (96,000 plants/acre)244,500 plants/ha (98,900 plants/acre)100%
40%222,300 plants/ha (90,000 plants/acre)160,600 plants/ha (65,000 plants/acre)158,100 plants/ha (64,000 plants/acre)163,000 plants/ha (66,000 plants/acre)87%
20%111,200 plants/ha (45,000 plants/acre)81,500 plants/ha (33,000 plants/acre)79,000 plants/ha (32,000 plants/acre)81,500 plants/ha (33,000 plants/acre)62%


Winter cereal forage harvest has continued or started in many areas of the province this week. First cut hay is generally limited at this point, but some may be starting over the next week. Staging may be slightly delayed compared to recent springs and fields should be scouted for appropriate crop stage for end use. Fields should also be scouted for alfalfa weevil. When possible, early harvest is a preferred control option. Other control options can be viewed at the Crop Protection Hub HERE. More details on Alfalfa Weevil management are available HERE.

Weather Data – May 15-21, 2023

LocationYearHighest Temp (°C)Lowest Temp (°C)Rain (mm)Rain (mm) April 1stGDD 0C April 1stGDD 5C April 1stCHU May 1st
10 YR Avg. (2011-20)21.98.418.218510258309
10 YR Avg. (2011-20)22.76.819.620463216278
10 YR Avg. (2011-20)
10 YR Avg. (2011-20)21.95.716.016457212274
10 YR Avg. (2011-20)
Mount Forest202323.1-2.011.211428213195
10 YR Avg. (2011-20)21.54.418.118366143217
10 YR Avg. (2011-20)22.43.712.713391160240
10 YR Avg. (2011-20)22.55.413.213413183254
10 YR Avg. (2011-20)20.82.414.31423487173
10 YR Avg. (2011-20)
Thunder Bay202325.80.029.830261103155
10 YR Avg. (2011-20)
Fort Frances202325.12.03.84332168254
10 YR Avg. (2011-20)20.10.620.22026285175
Report compiled by OMAFRA using Environment Canada data. Data quality is verified but accuracy is not guaranteed. Report supplied for general information purposes only. An expanded report is available at

Breakfast Meeting Minutes

Winchester Breakfast Meeting Notes (Zoom)

May 24, 2023


  • Most of the region got rain on Saturday (generally around a half inch, less to the east, more to the west)
  • Rain across region Wednesday morning
  • Frost damage – not a lot up but some soybeans planted in the April 15-20th window saw damage. Most beans that were damaged were cotyledons emerged or early first unifoliate.
  • Agricorp reporting some winter canola damage and some soybean damage
  • Some alfalfa scorching from the cold last week
  • 238 Crop Heat Units in Kemptville as of yesterday. Last year was 344. 10 year normal is 308. So little behind after being a little ahead.
  • Estimates are 95% corn planted, 75% soybeans. East of Ottawa, heavier clays, a little less.

Winter Cereals:

  • Flag leaf is just ready to emerge in some areas.
  • Late app of T1 fungicides happening – challenges around wind and weather to get it done
  • No heavy weed pressures yet – PGRs and fungicides have been focus.
  • Pest and disease pressures are low
  • Some Cereal Leaf Beetle way lower even in hotspot areas this year, armyworm is also low, but we haven’t had any major thunderstorms to bring up from the US
  • Seeing lots of physiological flecking in winter wheat due to prolonged cloudy weather followed by sunshine. Differences in varieties, can get quite severe. No controls options. Reported across the province, not just Eastern Ontario
  • Sulfur deficiency showing in fields with S and manure history. Suspected issues with reduced nutrient uptake (cold and wet weather suspected to be at fault). If you’re confident its Sulphur or Manganese deficiency, try to correct it right away. (e.g. second pass of N, add sulfur, bump N rates)

Spring Cereals:

  • Intended acres slightly lower than average – growers who need it grew it, growers who didn’t have a market for straw left it out
  • Any cereals planted May 8-10 are more uniform and catching up with cereals planted late April 
  • In general 3-4 leaf, GS 30ish. Some no till wheat not happy with cold, even without herbicide applied. Some damage from the frost but nothing detrimental at this point.
  • Some patchy spring cereals. Not whole fields replanting, but some areas of fields


  • General estimates are 95% of corn is planted
  • Some replants for mid-April corn. Stands were poor, soil conditions were not ideal at the time of planting
  • Corn should be emerging any time now – May 9th planted corn was emerging May 21-22nd


  • Replanting is occurring for soybeans planted April 15-16th – they’ve sustained too much frost damage. Populations weren’t awful, but very patchy and variable
  • Soybeans planted May 9th-10th are up if they were planted into moisture

Weed Control:

  • Struggles reported with wheat applications and highly variable temperature swings
  • Some concerns that rainfall didn’t come in time to activate some of the soil applied/pre emerge herbicides. Need half an inch – 5mm doesn’t do it. 5mm brings weeds on but doesn’t activate herbicides. Efficacy drops by 15-20% after 7-10 days without an activating rainfall
  • Not a lot of herbicide on the last couple weeks – wind almost every day, cool temps as well. Not a lot of pre, but more likely an early post application
  • Weeds really weren’t emerging until we got some rain this past weekend
  • South of Winchester doing lots of pre emerge, looking for 10mm rain today to activate
  • Poor dandelion control in wheat and even some burndown, cold may be a factor
  • Dandelion is most tolerant in full bloom – before or after bloom is better than flowered dandelions
  • Some horsetail pressures coming on strong the last couple weeks. Usual spots and pressures. Frosted over brown horsetail in some areas. Recommend waiting for regrowth – the control is better with the more green regrowth you can have.
  • South side of 401, km East of Maitland road, going to be some wild parsnip control with MTO. Updates to come as we find what works and what doesn’t. Hoping to spray next week.
  • Ideally a 5 year trial. Looking at how often and when to manage, etc
  • Classic with high rate of 2,4-D has had some success in fence line control. Once Parsnip over 20cm in height, they tend to get fairly tolerant to herbicide controls
  • Some fall control products aren’t effective in the spring (ie Distinct, dicamba)
  • Trying to push vegetation management to fall control applications for better efficacy and less off target drift


  • Forage rye being cut. Nutritionists suggesting to delay cutting higher alfalfa content fields until next week. Grasses are heading out and advancing but alfalfa is slow, buds just starting to be felt
  • Some forage that didn’t get early fertility is showing some stunting
  • Rye is early heading. Cereal rye that was planted early is heading out. Feed quality on forage rye is dropping quickly.


  • Deadlines are as follows:
    • June 15th for corn planting,
    • June 30 for soybeans
    • June 30 for reporting acres,
    • Invoices for premiums will be due July 10th
    • Any damage needs to be reported by June 15th.

Exeter/Simcoe Breakfast Meeting Notes (Zoom)

May 23, 2023


  • Last week was excellent for getting field work done – probably one of the fastest planting windows
  • Most areas have 95-99% of the corn planted. 85-90% of soybeans have been planted with a few IPs left to go in the ground as we move into edibles.
  • Rainfall from Friday through Saturday ranged from 10 to 40 mm across various areas.


  • There was discussion on whether herbicides such as primextra or integrity would have the ability to pull back already emerged foxtail.
    • It was noted that Broadstrike and Converge are the only two herbicides to claim to have reach back activity.
    • While other soil applied herbicides will still have an impact on emerging weeds after an activating rain, they will not pull down already emerged weeds.
    • Even for broadstrike and converge to pull back emerged weeds, the application, weed staging and weather conditions have to align perfectly.
  • There is value to soil applied herbicides in the first 7-10 days but in terms of emerged weeds you will have to control them with a post emerge herbicide.
  • It was noted that it would take a lot of grass to have an impact on yield and with growers coming back at 5 leaf corn with glyphosate it is not a major concern.


  • Approximately 95-99% of the corn has been planted.
  • Corn that was planted the week of April 9th is looking a little thin but is fairly uniform.
  • Few corn emergence issues so far. Anticipate seeing some with crusting in some fields
  • It was noted that growers should be patient for their corn to emerge. If the seed is still in good condition in the ground let it be.
  • Discussion on how deep to go into moisture with last corn being planted last week


  • Approximately 85-90% of soybeans have been planted. It was noted how quickly they went into the ground. There are a few IPs left to go in the ground.
  • A lot of grower questions about how deep to plant soybeans in the dry conditions.
    • Some growers were planting below 2”. Not ideal but with warm weather it should not be an issue on lighter soils, but there can be issues on heavier soils.
    • Some noted they prefer growers to plant at 1 -1 ½” and wait for rain.
  • There was discussion about soybean populations. Even at populations as low as 80,000 plants/ac you have 95% yield potential if you have a uniform stand.
  • Also noted that it can take soys quite a while to emerge. Growers are reminded to be patient for all the beans to emerge.
  • There have been questions around how many days after planting can you roll your beans or should you wait for them to emerge.
    • Do not roll beans when they are knuckling and breaking through the soil surface.
    • Wait for them to be at unifoliate or first trifoliate. Research in Ontario has gone as late as 2nd trifoliate without yield impact from a smooth roller on a hot afternoon.
    • No number of days that need to be within planting but usually 2-3 days is fine.
  • On the heavy clays in Niagara and Lambton they are making good progress, estimated 65-70% of soybeans planted.
  • In Niagara growers were struggling to get soybeans down into depth and asked about how deep they should go into moisture.
  • ½” rain was enough to soften the crust and boosted field activity.
  • It was noted that it is pretty rare that we can say by May 23rd we have 2/3rds of soybeans in the province which is a pretty awesome start. Often on those clays it is into late June/July.


  • Physiological flecking is being seen in winter wheat fields
    • This is expected after significant grey and cloudy days through April and early May
    • Can appear worse where the leaf bends and gets more intense sunshine.
    • Intensity is also variety specific with some being worse than others.
  • Powdery mildew is also appearing worse in some fields compared to others. Growers should look at the OCCC data to determine their variety’s level of disease resistance.
  • Some fields are showing signs of sulphur deficiency even where there is a history of manure or S applied.
    • Also showing overlaps, tire tracks and tile runs that are darker green
    • Suggested that the cold, wet spring may have had an impact on nutrient availability and uptake.
    • Also suggested that the cool, wet weather in April may have impacted or damaged roots more than we realized having impacted nutrient uptake.
  • Have also been fields that have not shown signs of manganese deficiency but tissue testing shows deficiency there.
  • If taking tissue samples for sulphur, manganese or other nutrients, ensure the latest emerged leaf (flag leaf) is sampled. Collect at least 50 leaves or fill a brown paper lunch bag ½ to 2/3 full.
  • Also discussion on the differences being seen between dry and liquid fertilizer in wheat fields. It was noted that if there are differences in the amount of S applied that could have an impact or the amount of rainfall received since the product was applied could have also had an impact.


  • First cut hay coming off over the weekend in Chatham-Kent for fields that were mostly grass and potentially being planted to corn or soybeans
  • In some areas you could hardly feel alfalfa buds at the end of last week, so it is still early. More is expected to start coming off at the end of the week.
  • Forage rye and triticale harvest continues.
  • Alfalfa weevil has been reported in Haldimand/Niagara.


  • Some major damage on tomatoes with some replanting occurring in Chatham-Kent.
  • Georgian Bay region had 2 hours of -6°C and significant damage on early budding/flowering apple varieties. Anyone that didn’t have a frost protection strategy are expected to be worse.
  • Some reporting frost damage on wheat.
  • No reports on losses in canola.


  • Very few damage reports to date.
  • Emergence is expected in 5-10 days, will get an idea on damage then or the crop that went in a little less than ideal conditions.
  • Crop inspections will dictate emergence and replants.

Northern Ontario Breakfast Meeting Notes (Zoom)

May 24, 2023

Dr. Tarlok Singh Sahota gave an update on two projects underway at the Lakehead University Agricultural Research Station in Thunder Bay. The first project is a nitrogen source trial on winter wheat comparing urea, urea + ESN, Anvol (NBPT + Duromide), and Super U with a double inhibitor (NBPT + DCD). Each of these products is designed to reduce nitrogen losses to the environment. ESN is a slow-release coating that reduces the portion of nitrogen available for loss early in season, releasing it closer to plant uptake. NBPT is the active ingredient in Agrotain and it reduces volatilization, which is nitrogen lost to the air. Duromide also reduces volatilization. DCD reduces N losses through denitrification and leaching. This trial is in the second of three years.

The second trial is looking at the effects of fall rye on spring-seeded grain and oilseed crops. Cover cropping in climates with a short growing season is always a challenge. The treatments in this project are fall rye with fertility, fall rye without fertility, and no cover crop. Last year’s results suggest that rye may affect the next crop in the rotation, but there are another two years to go in this project before there will be final results.

For growers considering summer seeding alfalfa or alfalfa/grass mixes:

  • Seeding rate 12-20 lbs pure live seed/acre. Go to the high end of the range if you have concerns about seedbed quality, or if broadcasting, especially if packing after broadcasting might be difficult.
  • Don’t use a companion crop, it will steal all the water from the alfalfa.
  • Optimal planting timings balance killing frost dates, average moisture, and time for the crop to develop a crown and be able to overwinter. In areas that typically get less than 2,700 CHUs, the optimal date is between July 20th and August 1st. Optimal dates for 2,700 to 3,100 CHUs is August 1-10.

Sandhill cranes and crop damage:

  • Sandhill cranes are causing damage to corn seedlings.
  • Control options are limited in Canada. Avipel (9, 10-Anthraquinone) isn’t approved here.
  • Trying other options for deterrents like scarecrows, noise bangers, etc., to see if any of those might work. Airports use balloons and kites to deter them, and some work has been done to test them in an agricultural setting, but they are costly.


  • In southern Ontario, true armyworm trap counts have increased recently. The last true armyworm outbreak was in 2020.
  • Cereal leaf beetle adults have been captured but in low numbers.
  • Iowa State has captured corn earworm early this year, which suggests we will see migratory pests early in Ontario as well.

District Updates:

Manitoulin Island:

  • Most crops (corn, barley, and oats) are approximately 50% planted.
  • Soybeans are closer to 80 to 90% planted.
  • Many producers are anticipating a second application of nitrogen to wheat in the coming days.  


  • Most of the corn in the ground.
  • Herbicide applications not on yet but will be soon.
  • Forage fields are doing great, and some cows have been moved to pasture.


  • Most crops are in the ground, but the area got 2+ inches of rain on Saturday.
  • Some replanting on winter wheat. Alfalfa is very behind this year.
  • Herbicides are starting soon.


  • Low temperatures and rain yesterday.
  • Lots of planting on the long weekend.
  • Oats emerged but not much else up yet.
  • Soybeans in but snowing today.
  • Canola trials at the Ontario Crops research Station – New Liskeard will go in later this week.

Thunder Bay:

  • Farmers are still applying manure.
  • Some corn and barley in but lots of planting still happening.
  • Rain delay for a day or so.
  • At LUARS – most planting is done and crops planted on May 11th have emerged and are looking good.

Rainy River: 

  • A few delays so not all acres are in but they are close.
  • Thunderstorms and winds last night. Not a lot of rain so shouldn’t be too delayed.
  • Alfalfa weevil and crucifer flea beetles are active. One field may need to be sprayed for alfalfa weevil.
  • Forage looking great this year and has allowed cows to go to pasture earlier compared to previous years.