Field Observations

September 25, 2025

As a new season arrived, so did a much-needed rain for the vast majority of southern Ontario. The corn milk line is progressing towards black layer, while the soybean harvest has had a strong start, as has winter wheat planting.

Corn

Corn milk line progression is between ½ and 7/8 milk line. The warmth of the past week really helped milk line progression move along. Black layer will be reached in the coming days for some hybrids.

Silage harvest is ongoing. Remember, silo gas with silage harvest can be a significant concern, especially in drought-stricken areas. For more information on risks and management from OMAFA, please visit here.

Soybeans

The soybean harvest rolls on with as close to perfect weather as anyone could ask for, up until Sunday night—sunny, warm days followed by a well-timed rain. The rain will help even out mature soybean fields and raise the seed moisture in areas that experienced early maturity within fields. Field Progress shares that the soybean harvest is at 20 per cent complete, as of Wednesday, September 24, 2025.

As soybean fields are harvested, it is a great time to test them for Soybean Cyst Nematode levels. Sampling is an important part of managing the pest, along with variety choice and crop rotation to a non-host crop. Ideally, fields should be sampled every 3 years. More on sampling and the implications of SCN on soybeans can be found here.

Are there suspicious weeds being found in soybean fields? A good first step is to consult with a local agronomist to help identify the weed and determine its potential causes.

For further insight, two testing services are available in Ontario to determine if plants are herbicide-resistant.

Plant bioassay testing by the University of Guelph– This service is offered through the University of Guelph, and requests mature seed collected in the fall to be submitted. Due to the seeds required, this is a great option later in the fall if plants have been frost-damaged but have viable seeds. Plants are then grown from the seed and sprayed with various doses of the herbicide(s) that are suspected to be resistant to. Results are typically provided by April. The service is provided at no cost to Ontario farmers.

Molecular testing by TurnKey Genomics (private lab) – The molecular testing service requires plant tissue that is roughly “loonie-sized”, so a single leaf is often adequate. Results are shared in a matter of days. Grain Farmers of Ontario helps fund some of this testing through OMAFA.

With respect to perennial weeds, there is an excellent article from OMAFA on fall herbicide applications and maximizing the impact on perennial weeds shared here.

Cereals

According to Field Progress, the spring cereal harvest is 91 per cent as of September 25, 2025. Winter wheat planting is at 13 per cent as of September 25, 2025. A well-timed rain this past week has helped any wheat that is in the ground germinate.

Mental health

As the fall arrives, take time to celebrate successes, whether big or small. Harvest is a stressful time of year. Be sure to take the time to get the support needed. Several support resources are available here.