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Ontario Grain Farmer Magazine is the flagship publication of Grain Farmers of Ontario and a source of information for our province’s grain farmers. 

Field observations


June 30, 2022

Much of the province could use a good rain, as soil conditions are drying out with the warmth received over the past week. For the next five to seven days, there appears to be limited moisture on the way for much of the region. Crops continue to progress well with limited disease or insect pressure, yet.



Much of the corn crop has canopied over the last week, with some areas well-surpassing knee-high and heading to waist-high. Corn stages range from V5- V11. At V9, the tassel is rapidly developing but is not yet visible at the top of the plant. New leaves appear every 2 to 3 days, and ear shoots are also developing.

Some Nitrogen is still being side dressed on the more advanced corn fields.

Grain Farmers of Ontario and Tracey Baute, OMAFRA entomologist, recorded a recent #GrainTalk webinar highlighting various pests to be on the lookout for across Ontario fields this season. Find out more about scouting, trapping, monitoring, and resistance of pests such as corn rootworm, spider mites, and more.


Soybean staging for much of the province’s crop is anywhere from V3 (3 trifoliates) to R1 (beginning bloom – at least one flower appears on the plant on any node on the main stem). Staging is important as the season progresses to be able to apply herbicides, fungicides, and insecticides safely and effectively as required.

Fungicide timing is approaching for white mould control (find out more about white mould). The key to getting the most benefit out of fungicide applications is timing. Risks for white mould include the field history. If there is a known history of white mould, then the chance of it reoccurring is high. Variety, row spacing, plant density, and how quickly the field will canopy all factor into the likelihood of infection. Weather patterns will also help determine the risk. When it is foggy/humid and moisture is on the plant most of the day, there will be a higher risk of white mould. The Sporecaster App can help you determine your field’s risk level. Fungicides can lower the severity of infection; however, timing is critical. The application timing ranges from R1 (single flower on the main stem) to R3 (pod on the main stem). Be sure to speak with your agronomist for optimum timing and product selection, and always follow label recommendations.

A reminder as the season progresses that Grain Farmers has supported the development with OMAFRA of the Pest Manager app, which allows you to identify, map, and find integrated management options for common weeds, insects, and diseases in corn, soybeans, and cereal crops. The pesticide use information in the app is specific to Ontario, and users should always read the product label before use.


Wheat across the province is showing variability on maturity depending on how much rainfall was received in June. Some areas are drying up and maturing quickly due to the little moisture during grain fill. Harvest will be starting within the next week in some southern regions. Wheat harvest occurs quickly after maturity is reached once grain is dry enough for harvest. The longer wheat is left in the field, the greater the risk of reduced grain quality. Rain showers occurring after the grain has matured cause kernels to rewet and can result in kernels sprouting. The development of sprouts, even before they can be seen with the eye, results in lower falling numbers (falling numbers is a test that helps identify the structural integrity of the starch chains and determines how well suited the flour is for baking).

Maturity on wheat can be determined by the peduncle changing from green to yellow. At this point, the crop is fully mature, grain fill and the translocation of plant sugars have been completed (this stage can be compared to the black layer on corn). It takes roughly 660 growing degree days (GDD) to fill a wheat head. This period of GDD gains spans approximately 25 to 30 days for grain fill (less if it is extremely warm) – not a very long time.

Wheat peduncle has turned yellow signifying
maturity has been reached.

With the early wheat harvest, double-crop soybeans are a common conversation in some areas. If aiming for double-crop soybeans, seed supply on early-season beans will be needed. The date of wheat harvest and the field location will determine a lot. Aim for seed maturity that is at least one full maturity group shorter but check with your seed dealer on what they suggest and what is available. The seeding rate should be increased to at least a population of 250,000 seeds per acre. The planting date should be considered, looking at frost dates, as the yield potential will drop considerably if soybeans are planted too late. Early to mid-July planting dates are ideal, be sure that the soybeans are going into good conditions. The ideal planting dates for double-crop soybeans would be before July 10 for southwestern Ontario and before July 20 in the deep southwest, but it is a large risk at any date; the soybeans might yield, or they might not. Managing straw is critical, be sure to spread straw and chaff evenly. If you are considering baling, realize that the time spent baling might keep you out of the field planting for a couple of days. If you plan to double-crop soybeans, plant to moisture – up to 3” in July as they will push through. If there is no moisture at that level, aim for 1” planting depth and hope for rain.

The need for weed control in double-crop soybeans will be less – in theory, one pass would still be needed to control weeds. Most annual weeds emerge during May and June, and if double-crop soybeans are planted in July, weed pressure should be considerably less. Limit the investment in weed control as the chance for good soybeans is less likely with much relying on the weather cooperating for a good yield and harvest so late in the season.

June 23, 2022

The first day of summer came in hot for much of the province. Heat has been drying out some of the wetter areas of the province, but it is also reducing soil moisture where rainfall has been short over the past few weeks. Variability in fields is evident this year, showcasing last fall’s wet harvest.  

Corn, soybeans, and cereals are progressing quickly as high heat is being received. The Elora area is currently at 735 growing degree days (GDD) as of Monday, June 20. 725 GDD were received in the same time frame in 2021. For comparison, Ottawa Agriculture and Agri Food Canada is showing 815 GDD as of June 20, 2022, and the same time frame received 824 GDD in 2021.


Corn across the region is looking good, and as the old saying goes, much of it will be “knee-high by July 1”, if it isn’t already. However, as one travels the province, there is still a high degree of variability in how the crop looks. Corn rows are beginning to close, with the most advanced corn staging roughly at the V7 (9 leaf) stage. Growth will progress quickly with the upcoming warm days, and some shoulder-high corn can be expected by July 4.

At about the V6 stage (six collars, or 8 leaf stage), the growing point emerges above ground level. The critical stage of ear development is from this stage to about a week before pollination. Ear initiation starts, then the kernel rows per ear are determined. The number of kernels per row is determined as the ear elongates and is determined before pollination. Stress in the upcoming weeks from lack of nutrients or moisture will reduce grain potential through reduced kernel numbers. Stress can be caused by many factors like too high population, weed pressure, root pruning from machines or insects, lack of fertility, lack of rainfall, standing water, hail damage, disease, etc.

Rapid growth syndrome has and can be seen in fields with the change from cool to high heat. This can be seen in the field when corn leaves do not unfurl properly, and the whorl becomes tightly wrapped and twisted.


Soybean stages are across the board. Some regions are finishing replants, while others finish their first planting as frequent rains have delayed planting. The most advanced fields are around the V4 to V5 stage (4th to 5th trifoliate). However, most of the crop is in the early V1 to V3 (1st to 3rd trifoliate) stages.

In the V3 to V5 stages, axillary buds develop into flower clusters near the top of the stem. In the coming days, flowering will begin, starting on the 3rd to 6th nodes and continuing down the stem. At this point, the plant will transition into reproductive stages (R1) while continuing to grow vegetatively.

Overall, preemergent herbicide applications have worked very well for weed control, thanks to the timely rains.

If soybeans were planted into hay ground, be sure to take a walk around and assess insect damage. Seed corn maggot has been found in soybeans fields that were planted after hay, even with an insecticide treatment.

The province’s northern region received some very cool temperatures over the weekend, and some frost damage has been seen on muck soils.


Winter wheat is quickly approaching maturity in the extreme southwest portion of the province. Ensure that combines are ready to roll when the time comes. As harvest approaches, scout for fusarium damaged heads in the field. Infected fields should be harvested first to limit continual toxin build-up in case of rain events or delayed harvest. Set the combine correctly to help blow out the lighter infected kernels.

Across the province, kernel fill is occurring in the winter wheat crop. Prolonged hot, dry weather will limit kernel fill resulting in smaller kernels as the water availability for the crop becomes limited. Kernel abortion and dead heads can be experienced as the plant dies rather than matures if moisture becomes too limited during this period. Flag leaves are already starting to senesce as the plant moves nutrients and moisture from the leaves to the kernels to help finish kernel development. Cracks in the soil are appearing in some regions of the province where rainfall has been limited. The fibrous root system of the wheat crop extracts all the moisture it can as it finishes grain development.

Farmers should be on the lookout for aphids in oat fields, as there are some reports of higher numbers in this crop. These aphids are a vector for barley yellow dwarf virus. The economic threshold for aphids on cereals is an average of 12 to 15 aphids per stem before the soft dough stage. After the early dough stage, insecticide treatments would not be cost-effective. Check the interior of the field and not just the edges. Consider the crop stage, beneficial insects, plant stress, and threshold before spraying. Plants that become infected with the virus transmitted by the aphids may be severely stunted and not head out.

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