Ontario Field Crop Report – Week of June 24th, 2019


Grain corn planting is complete on intended corn acres except on heavy clays that received more rain this week. Crop stages range from 8 leaf stage to newly emerged. Overall plant stands look good on lighter and medium textured soils although plant stress is becoming evident on corn seeded into less than ideal conditions. There were reports of tough looking corn with very hard ground 2 inches below the surface and plants turning colour after 3 or 4 days without rainfall. There is concern that if conditions turn dry now these fields will struggle, due to a delayed root development primarily caused by seed trench compaction. There is also still some silage corn being planted. Majority of corn has received some of its nitrogen and much more is planted as side-dressing and later top dressing.

Uneven stands are hard to diagnose between cool wet weather or emerging pest pressure. Black cut worm pressure in some areas, which matches up with model predictions.

Herbicide applications have been delayed this year in some fields and weeds are very large before they are controlled. Weeds that emerge at the same time as the crop cause the greatest yield losses. Although soybeans will lose yield to weed competition they are less susceptible than corn. Prioritize you weed control applications to the fields that have the most urgent need and will offer the best response to the herbicide program.    


Soybean stands seem to be good so far. Fields vary from newly planted to fully emerged. The earliest fields of narrow row beans are beginning to fill in with some achieving second trifoliate stage. Replants are underway on clay soils where seed was planted too deep or stands are thin for a variety of reasons including crusting after rain. The soybean and edible planting date deadlines have been extended to July 5th. With respect to the unseeded acreage benefit (USAB) a grower may now change their dominant crop up to July 5th. Please contact Agricorp to discuss coverage.

Pre-emergent herbicides have been doing an excellent job this year resulting from adequate activating rainfall. A considerable number of fields did not get a burndown and have very large weeds now. Read herbicide labels to understand timing and performance. It is important to following good herbicide stewardship practices like considering wind speed, application volume, ground speed and neighbouring crops.

Should fields that are planted now be switched to earlier season varieties? The general rule of thumb regardless of planting date (even double cropping) or geography is to seed the longest maturing variety that will finish normally in the fall before a killing frost.

After June 15th shortening a variety by 0.5 to 1.0 maturity group is a reasonable strategy to ensure timely fall harvest. However, growers in areas with more than 3000 crop heat units may opt not to switch varieties since those areas are more likely to have an open fall. If planting is delayed past the first few days of July switching to earlier season varieties is the best strategy to ensure crops mature this fall.

The presence of seed corn maggot in some soybean fields has been observe.


Spring cereal stands are generally in good shape and progressing well with the below average temperatures and good soil moisture.

The risk for fusarium head blight in winter wheat remains high. It’s estimated that up to 90% of the wheat received a T3 fungicide. Heading dates were variable so deciding the exact date to spray was very challenging. Overall, the crop is likely about 2 weeks behind normal development.

Cereal leaf beetle (CLB) is being reported in several winter wheat fields and will likely begin to move into spring cereal stands. If the crop is after the boot stage but prior to heading the threshold is one CLB larva or adult per stem. Watch for pre-harvest intervals if timing is getting late. 

Physiological fleck and aphids are also being reported in winter wheat fields. Thresholds for aphids are up to the boot stage; if the crop is beyond this stage, treatment has no merit. Populations may begin to increase in spring cereals, however, natural enemies will hopefully build up before that. If young plants have 12-15 aphids per stem up to boot stage and natural enemies are not present, control may be warranted.


The earliest planted spring canola, primarily in Bruce and Grey counties on lighter ground, is approaching flowering. These fields represent typical spring canola planting and flowering timings. Most of the spring canola was planted in late May or early June and is still in the rosette stages. Flea beetle were present in many fields and numerous fields were sprayed with an insecticide. Some crop scouts have noted flies in the fields, which are likely Delia species (such as seedcorn maggot flies or others). The adult flies will not cause crop damage but check for maggots feeding on the roots. However, it is not expected that the maggots are causing much damage. Many flies have been observed dead and stuck to the top of canola plants; these have been killed by a beneficial fungus.

Winter canola varieties at the AAFC Harrow Research Station that are defined as “early” varieties are starting to show signs of seed colour change. “Regular” winter canola varieties will likely mature about a week later. Spring was late this year, so harvest of winter canola in southwestern Ontario will likely occur towards the end of July.

Dry Beans

Dry bean planting is ongoing between rain events. Reports from Huron and Perth indicate up to 20% of dry beans remain to be planted as of June 23. Bean emergence has been quite slow, particularly for larger seeded beans like cranberry and kidneys. Soil temperatures of 18 (°C) and above are best for quick dry bean emergence, so relatively cool temperatures may have been the cause of slow emergence. Crusting is also an issue in some fields. There have been reports that slow emergence has led to some bean cotyledons rotting. When considering replanting dry bean fields, factor in the harvest date as well. Stands with 2 to 3 healthy plants per foot of row on 15” rows and 3-4 on 30” rows, with an even distribution of healthy plants, should yield reasonably well. Later plantings may lead to more quality issues at harvest time.


Harvest of first cut hay continues throughout the province and the harvest period has extended for several weeks compared to typically one week. First cut yields range from average to below average. Forage quality is unknown until lab results are completed in next few weeks. Improved weather conditions are helping cow calf grazing in last ten days. Some livestock producers continued planting silage corn earlier this week to boost forage inventories. Producers who have established alternative forage crops are reminded that it is generally 45-60 days from planting to harvest, depending on the crop. More information on alternate forage options is available at fieldcropnews.com.

Figure 1. Tile drainage demonstration day at Huron Soil and Crop Demo Farm

Figure 1. Tile drainage demonstration day at Huron Soil and Crop Demo Farm 

Please visit Field Crop News for further information including timely breakfast meeting reports. https://fieldcropnews.com/2019

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