Ontario Field Crop Report
2010 Corn Seasonal Summary

Table of Contents

  1. Summary
  2. Growing Season
  3. Corn Pest Problems
  4. 2011 Outlook

Technical information can also be obtained at the OMAFRA Field Crops Webpage and Crop Pest Ontario. Referenced OMAFRA Publications include the Agronomy Guide for Field Crops (Publication 811), the Field Crop Protection Guide (Publication 812), Guide to Weed Control (Publication 75), and Ontario Weeds (Publication 505). These can be obtained from your OMAFRA Resource Centre, or by calling 1-800-668-9938.


The 2010 corn growing season was excellent! Conditions early in the season were very conducive to early planting. The 2010 growing season was characterized by adequate rainfall in nearly all parts of the province; a distinct lack of stress during flowering allowed for excellent pollination. Ontario Crop Heat Unit (CHU) accumulation was above the 30 year normal for nearly all locations in the province. For example, the CHU accumulation (May 1 to season-end) at London was 8% above normal, Mount Forest was 5% above normal and Ottawa was 4% above the 30 year normal.

Corn yields were record breaking - with 95% of the yields submitted to Agricorp, the provincial average stands at 172 bu/ac (10.79 tonnes/ha); undoubtedly, when all acres are reported this will result in a provincial average yield that is significantly higher than any previous year. Prior to 2010 the highest OMAFRA provincial average corn yield was 156 bu/ac (9.78 tonnes/ha) in 2008.

The 2010 harvested grain corn acreage was 1,860,000 acres (753,000 ha). The early start to the season coupled with high CHUs and good harvest conditions meant that virtually all the crop was harvested before winter set in.

Growing Season

April weather was abnormally warm and relatively dry resulting in perhaps the best soil conditions and earliest corn planting ever experienced in the province. It is estimated that between 80 and 90 percent of the corn was planted by May 5th. Early planting and warm conditions resulted in much of the crop emerging in late April or early May and effectively added 150 CHU to the season. London for example, accumulated 3404 CHU from May 1 to season end, but for growers that planted in mid-April the effective CHU total for those areas was closer to 3550.

Ground frost, with temperatures in the - 1 to - 4 C range on May 9 or 10 damaged much of the emerged corn. Green tissue ranging from the spike to 3 leaf stage was frozen to the ground in many fields. The corn recovered from this damage relatively quickly. There were some reports that the frost damage caused increased variability in some fields.

Rainfall was low throughout August in many areas and combined with corn that had flowered relatively early (July 10-20) meant that silage harvest was very early with some producers being finished silage harvest before September 1. Dry conditions in August did become severe enough to reduce corn yield significantly but these situations were quite isolated.

In some areas stalk quality became an issue as the grain corn harvest developed. Corn plants that had attempted to meet relatively large starch demands for grain filling resulted in increased levels of stalk cannibalization and lodging. Yield losses due to these conditions were for the most part minimal. On average, grain corn harvest moistures were abnormally low resulting in significant drying cost savings for many producers.

Corn Pest Challenges

Western Bean Cutworm (WBC) continued to be a significant concern across many areas in 2010. The number of counties where the WBC moths were trapped increased and moth numbers increased dramatically compared to previous years in some counties. In isolated areas the presence of egg masses and larvae reached the threshold where control was required. In very isolated areas the insect feeding was significant, to the point that if no control measure was in place (either genetic protection or insecticide application) yield losses approached 15-20 bu/acre (.94 - 1.26 tonnes/ha).

Leaf and stalk diseases were generally quite low in 2010. Ear mould presence was also below normal and vomitoxin in the corn generally did not represent a challenge in terms of grain corn end use. A survey conducted at the beginning of the harvest period reported vomitoxin (DON) at less that 1 PPM in 76% of the samples gathered.

2011 Outlook

Optimism is high for corn in 2011 due to the high productivity of the corn crop in 2010 and more favourable commodity prices. This is tempered somewhat by increasing input prices including fertilizer, seed, and land rents. Other areas of particular interest in 2011 include, 1) monitoring WBC development and in some areas focusing on hybrids that offer genetic protection, and 2) nitrogen and other input recommendations in the face of higher yield expectations.

For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca