OMAFRA Field Crop Report – May 07, 2020

Air temperatures for the week of May 4th were below the seasonal average. This has slowed soil warming and while not hindering planting, it is delaying germination and emergence of seeded crops. But so far, the 2020 season has offered better planting conditions than the past number of springs.


Most of the winter wheat crop looks excellent although the prolonged cool conditions have slowed growth. Some of the later planted winter wheat fields are struggling but people are wanting to keep these because of the current market pricing. Growth of annual weeds continues to be slow but is starting to get to the stage when herbicides should be applied. However, forecasted cold air temperatures (<5°C) can increase the potential for crop injury from herbicide applications and therefore will be delayed until air temperatures increased during the latter part of the week of May 11th.

There is more interest in plant growth regulators (PGR’s) this year. With the very good crop, producers are wanting to optimize it. When considering application of PGR’s, tank mixes with herbicides and fungicides during these cold conditions should be avoided. Timing of application relative to crop and pest growth stage is the most important consideration. Even if no PGR’s are planned, delaying the herbicide application until overnight temperature forecasts are warmer is recommended. Weeds will not grow rapidly under these cool conditions.

Disease pressure is low across the province with Septoria being the only disease reported in the lower part of the canopy in some fields. Scout to determine if a fungicide is warranted. In general, disease pressure is well below threshold for triggering application.

Spring cereals are all planted with increased acres across the province, especially oats. Cereals are taking 7-10 days to emerge under these temperatures, but seed was planted into “fit” soils and everything should be fine.


Corn planting has progressed steadily during the week of the May 4th and planting conditions have been excellent. While corn seed planted 3 weeks ago has not emerged, the ground is not overly wet, which is when the problems of slow germination are of concern. With relatively low temperatures predicted, it is fine that the corn has not yet emerged.

The rate of planting varies widely within and between areas. Some people are completely done and moved onto soybeans while others are just started or yet to start. On average we predict that around 50% of the corn has been planted across Ontario with higher levels in the west and far east compared to the mid-west and central regions. Areas with heavier soils continue to wait on field conditions to be suitable.

Where corn is still to be planted, ensure uniform seeding depth of 1.5 to 2.0 inches. Uniform depth is key to ensuring uniform emergence which provides excellent start to corn achieving its yield potential.


Soybeans, like other crops, do best when planted under ideal soil conditions and for the most part, the 2020 planting season has offered this. Some have expressed concern over the cold temperatures predicted for May 7-11. Once moved into May, the expectation is that temperatures will only improve so if soil conditions are good, growers should continue to plant. The recommendation is to plant 1.5 inch or deeper if you need to find moist soil. The emergence of soybeans planted this week will be a bit delayed, which under current soil conditions is fine and low temperatures should have passed by the time emergence occurs. The goal with any crop is uniform emergence of equally vigorous plants and the 2020 planting season is allowing that to occur so far.


Much of the spring canola in the traditional southern Ontario locales is completed. Seeding has started in northeastern Ontario. Seeding should be completed by May 15 for optimal potential and to avoid damage from swede midge during early growth stages.


Cool conditions have kept growth slow in hay fields and pastures. Flowering in grasses is linked to day length rather than heat, so this may reduce yield at first cut, especially for growers prioritizing quality. Scouting should focus on stem counts to assess alfalfa yield potential. Fifty-five or more stems per square foot (ft2) provides full yield potential; stands with fewer than 40 stems/ft2 have less than 70% yield potential and may need to be terminated after first cut. True armyworm scouting in grassy fields should start in the next couple of weeks where fields were green in April.

Figure 1. Corn planting in Perth county on May 5th.
Figure 1. Corn planting in Perth county on May 5th.
Figure 2. Corn planting into bio-strips, in Huron county on April 26th.
Figure 2. Corn planting into bio-strips, in Huron county on April 26th.