Ontario Field Crop Report
2007 Soybean Crop Seasonal Summary

Table of Contents

  1. Summary
  2. Planting
  3. Growing Season
  4. Soybean Pests
  5. Harvest
  6. Challenges for 2008

Technical information can 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.


Soybean production was challenged this year by a lack of moisture along with various insect and disease issues. Yields were extremely variable, ranging from 7 to 55 bushels per acre (bu/ac), depending on rainfall, soil type and pest pressure. Generally, yields were below average. With 20% of yields reported to-date, the provincial average at present is 33 bu/ac, compared to a 10 year average of 37 bu/ac. Seed size was smaller than normal, but quality was respectable. Green stems have been a challenge for harvest, but a dry fall has allowed for timely harvest of most fields.


Excellent dry spring weather and good soil conditions resulted in an early start for soybean planting. The majority of soybeans were planted May 5-25, the ideal planting window for most of Ontario. A few areas, such as Niagara, were so dry that germination was hampered and poor plant stands resulted. Due to the dry conditions, potash (K) deficiency was more evident this year, especially in fields with poor root growth or low K soil levels.

Growing Season

The 2007 growing season was close to normal in terms of Crop Heat Units (CHU). From May 1st to August 31st the average, across 15 Ontario weather stations, was 2570 CHU's in 2007. This compares to a 30 year average of 2544 CHU's. Precipitation was extremely spotty, but generally well below average in most regions. Soybeans need significant rainfall for optimum yields, especially during July and August. From May 1st to August 31st an average of 73% normal rainfall was recorded, compared to the 30 year average.

Soybean Pests

Soybean aphid pressure was high in some areas, but economic thresholds were only reached in eastern Ontario, and the region spanning from London to Wingham and east to Guelph, where aphids were found as early as late-May. Unfortunately, a few fields were so infested that multiple foliar insecticide sprays were required.

Bean leaf beetle pressure was high during spring and late-summer. Essex, Kent, Huron and Perth Counties had populations high enough to warrant spraying. Leaf feeding was evident in many fields west of Toronto and as far north as Bruce County, but below economic threshold levels.

Various other soybean pests, such as spider mites, stink bugs and soybean cyst nematode (SCN) were also prevalent. SCN continues to be detected in new parts of the province. This year, significant SCN was found in a number of fields in the Trenton area.


Low seed moisture at harvest resulted in losses and cracked seed coats. It was also common to see individual plants remaining green while the rest of the field dried down normally. Where green stems were numerous, yield and seed quality were reduced and harvest was delayed. Due to the dry growing conditions during July and August, many pods were aborted. These plants then had too much photosynthate in relation to the number of seeds, resulting in green stems at harvest time. The dry fall allowed for timely harvest, making way for winter wheat planting.

Challenges for 2008

Increased Pests

SCN was found east of Toronto for the first time in 2007. This pest will continue to invade new regions. Fields that struggle to maintain yields without obvious reasons should be tested for SCN. If SCN is detected, good management practices can be employed to minimize the impact. Bean leaf beetle populations have increased rapidly over the last few years. Not only do these insects feed on the leaves and pods, they also transmit bean pod mottle virus, which reduces seed quality. This pest is now a problem as far north as Huron and Perth Counties and will likely be a problem in coming years. Soybean aphids were detected much earlier than usual this year. Continued scouting and control measures will be necessary to reduce the yield impact of this insect. New aphid resistant soybean varieties, as well as new insecticides, are anticipated over the next few years to help control this insect.

Soybean Rust

Soybean rust spores were detected for the first time in Ontario in 2007, although no disease was detected. Spores were collected in traps in June and again in July and August as weather systems moved in from the United States. The spore load and viability of these spores was low. Soybean rust disease did move into new areas of the United States, such as Kansas, Nebraska, and Iowa. More soybean spores have also been found on the Kudzu plant in the southern US. This will further increase the spore load in 2008. Close monitoring of this disease continues to be essential. Ontario will need to be vigilant to monitor the spread of rust, and be prepared to apply control measures if necessary. Rust spore tracking, as well as the sentinel plot system, are being planned again for 2008.

Risks and Benefits of Identity Preserved (IP) Soybeans

The high Canadian dollar and better crush prices will challenge the Identity Preserve (IP) market. The adoption of Glyphosate Toleratant soybeans may increase again in 2008. Producers will continue to weigh the benefits and risks of growing IP soybeans.

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