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The Cropwalker - Vomitoxin Special

This is a special edition based a Twitter poll and individual conversations by Matt Pot of Grain Perspectives  -www.grainperspectives.com and Jonathan Zettler with Fieldwalker Agronomy - www.fieldwalker.ca . Thank you to Bayer CropScience Canada for sponsoring our work.


After a few conversations around estimating harvest progress, we felt it would be of benefit to paint a picture on where vomi is an issue and approximately how many acres are affected. Survey results were segmented by corn growing region to ensure a large enough sample size. Individual or county results may vary. See notes below for further information.

Vomitoxin Survey Results by Ontario Corn Growing Region


Eastern Ontario

We had 11 unique respondents, most replied that VOM was essentially a non-issue for the region. This area accounts for approximately 18% of Ontario corn acres.

Central Ontario

6 unique respondents for central Ontario commented that vomi tests ranged from 0 to 3 ppm. Again, essentially a non issue in an area that accounts for 10% of Ontario corn acres.

Western Ontario

In this region there is a wide range in results. Huron and Perth are by far the hardest hit, outside of those two counties average results are 5 ppm or less. There was a wide range in results from zero to 40 ppm. Even within Huron and Perth, the southern portion of both areas have high vom reports than those in the northern areas. Western Ontario accounts for 28% of Ontario corn acres, with Huron at 7%, and Perth at 6% of Ontario corn acres.

One anonymous source commented that there is a wide range in levels by corn hybrid for Huron and Perth. Christy Visser of CVP Crop Management mentioned that Simcoe County was 5 ppm or less, with one dual purpose hybrid running 11 ppm.

Southern Ontario

This area is by far the hardest hit out of the whole province and also had the highest number of respondents at 41. The average low value reported was 2 ppm, highest average vomi reported was 11.6 ppm, with 6.8 ppm being the mean value. Highest reported test results were concentrated in Lambton, Middlesex and Oxford. Limited reporting from Elgin, where higher test results were reported as well. This region accounts for approximately 44% of the Ontario corn acres.

Weather Maps

Agricorp provided several rainfall maps for the 2018 season. They help to paint the picture on which areas have had significant quality issues and the environment that created it. Make note of which areas were extremely dry during the growing season, only to turn wet during pollination/tasseling.

May 2018 Rainfall - Note the dry regions within the Province
June 2018 Rainfall
July 2018 Rainfall - Note the rainfall in Eastern Ontario
August 2018 Rainfall - Note the stressed areas that were wet during tasseling.

Source: http://www.agricorp.com/en-ca/News/2018/Pages/RainfallMapsMayJune.aspx