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Ontario Crops Progress with Cool Stress

 Ontario Crops Progress with Cool Stress
Jun 02, 2025
By Farms.com

Winter Wheat Heads as Corn Yellows and Soybeans Emerge

Ontario field crops are progressing despite challenging spring conditions, according to OMAFA's FieldCropNews.com.

Winter wheat has reached the heading stage in the southwest, with T3 fungicide applications beginning. Fields in the north and east are at the flag leaf stage. This is a key time for scouting, with optimal fungicide timing on “day 2” when pollination begins. Fusarium risk remains low during cooler nights but could increase with warmer, wet conditions.

Stripe rust is spreading beyond initial locations, including Chatham and Palmerston, according to FieldCropNews.com. Immediate fungicide application is advised if flowering is still over a week away. Powdery mildew is also present, especially in thick stands.

Corn planting is nearly 85-90% complete in well-drained areas but remains around 30-50% on heavy clay soils. In northern counties like Northumberland and Prince Edward, progress is delayed due to excess moisture.

Cold stress has yellowed emerged corn, but this is not due to nutrient deficiency. Herbicide timing should focus on the weed-free period between V1 to V10 stages. Most products are safe with rising temperatures. Side-dress nitrogen has begun on early planted fields, with 4 to 5-leaf corn in progress. Delivery coordination for UAN is advised.

Soybean planting is 65-85% complete overall. Wet soil has delayed progress, especially in Renfrew and Pembroke. Some replants are needed due to poor emergence and root rot. Early planted beans are emerging well, but growers must ensure herbicides match traited varieties to prevent crop damage. Clear records and field signs help avoid costly mistakes.

Spring cereals look uniform with no major disease issues reported yet. However, cereal leaf beetles may become a concern as T3 fungicide timing nears.

For more information about the cereal leaf beetle, please visit the Farms.com Field Guide Pest pages.


Trending Video

Wheat Yields in USA and China Threatened by Heat Waves Breaking Enzymes

Video: Wheat Yields in USA and China Threatened by Heat Waves Breaking Enzymes

A new peer reviewed study looks at the generally unrecognized risk of heat waves surpassing the threshold for enzyme damage in wheat.

Most studies that look at crop failure in the main food growing regions (breadbaskets of the planet) look at temperatures and droughts in the historical records to assess present day risk. Since the climate system has changed, these historical based risk analysis studies underestimate the present-day risks.

What this new research study does is generate an ensemble of plausible scenarios for the present climate in terms of temperatures and precipitation, and looks at how many of these plausible scenarios exceed the enzyme-breaking temperature of 32.8 C for wheat, and exceed the high stress yield reducing temperature of 27.8 C for wheat. Also, the study considers the possibility of a compounded failure with heat waves in both regions simultaneously, this greatly reducing global wheat supply and causing severe shortages.

Results show that the likelihood (risk) of wheat crop failure with a one-in-hundred likelihood in 1981 has in today’s climate become increased by 16x in the USA winter wheat crop (to one-in-six) and by 6x in northeast China (to one-in-sixteen).

The risks determined in this new paper are much greater than that obtained in previous work that determines risk by analyzing historical climate patterns.

Clearly, since the climate system is rapidly changing, we cannot assume stationarity and calculate risk probabilities like we did traditionally before.

We are essentially on a new planet, with a new climate regime, and have to understand that everything is different now.