A pre-harvest herbicide treatment can make harvest more efficient when there are an unacceptable number of weeds in a soybean crop. Both conventional and glyphosate tolerant fields that are weedy can benefit from a pre-harvest herbicide. Drier plant matter will pass more easily through the combine, lowering seed losses and reducing seed staining…
This post will serve as a repository for all information associated with the management and control of waterhemp in Ontario.
Mike Cowbrough May 3, 2020 841 Comments Off on Mixing “ATS” with herbicides: The importance of a “jar test”Each year I get more questions about mixing the liquid fertilizer, ammonium thiosulphate (ATS) with herbicides. With reductions in atmospheric Sulphur deposits, Ontario research has shown positive yield responses in some crops when Sulphur fertilizers are applied and so it makes sense that farmers are looking at ways to add Sulphur to their crop in an efficient manner. However, my…
Scentless chamomile has a reputation for being difficult to control and a 2019 on-farm research trial evaluated several herbicide treatments. Although 10 treatments provided over 80% visual control of emerged plants, new seedlings continued to emerge several weeks after application resulting in a significant amount of plants at the end of August. In order to significantly reduce the population of…
The following link will take you to a .pdf version of the wild carrot chapter from the book entitled “Problem Weed Guide for Ontario Crops – Volume 1”
Six tank-mix partners are recommended for the removal of Roundup Ready Alfalfa and since they vary significantly in cost (Table 1), their effectiveness was evaluated in a trial conducted at the Elora Research Station in 2018-19. Growing degree day accumulation after herbicide application appeared to have the greatest effect on the control of Roundup Ready alfalfa. Presumably because alfalfa has…
Mike Cowbrough March 22, 2019 2353 Comments Off on What’s Working on the Farm? Practical Solutions for Problem Weeds“Do not be cheap. Weed control is an investment into the current and future crops on every field.” That was parting advice from Norfolk and Oxford County farmer Ann Vermeersch at the 2019 FarmSmart Conference in Guelph. In front of 80 farmers and agronomists, I moderated a session with Vermeersch and Steph Kowalski, a Certified Crop Advisor and Lead…
Mike Cowbrough November 20, 2018 2333 Comments Off on Managing Glyphosate Resistant Canada Fleabane with Cover Crops and TillageMy colleague Dr. Clarence Swanton (University of Guelph) used to say that based on research he did in the 1980’s, one should not expect to control weeds with cover crops. Their utility was in preventing soil erosion and improving soil health but not in significantly reducing weed populations. However, Dr. Swanton has had to re-think his long held position on…
The OMAFRA Guide to Weed Control for Field Crops (Publication 75A) is available in the following formats: ELECTRONIC ENGLISH VERSION (PDF): click to download ELECTRONIC FRENCH VERSION (PDF): click to download PRINT VERSIONS: Go to Publications Ontario and search the term “Guide to Weed Control”
The latest best management practices for common ragweed competing in corn, soybean and winter wheat can be found here: Common ragweed control (Source: Problem Weed Guide for Ontario Crops)
Mike Cowbrough August 8, 2017 3031 Comments Off on Crop response to herbicides applied prior to and after emergence.For over 30 years, the Ontario Agriculture Weed’s team has competed in the Collegiate Weed Science Competition organized by the North Eastern Weed Science Society. In preparation for the “herbicide identification” portion of the competition, an area at the Elora Research Station is planted to a number of different crop and weed species and then sprayed with several herbicides. This training…
Volume 1 of the inaugural “Problem Weed Guide for Ontario Crops” includes management strategies for 19 species in corn, soybean and cereal crops that is cited from work conducted by the University of Guelph Department of Plant Agriculture as well as other peer reviewed studies. This 176 page guide features over 175 images and 50 tables that help illustrate the…
Mike Cowbrough December 5, 2016 6103 Comments Off on Has the adoption of genetically engineered (GE) crops resulted in more herbicide resistant weeds in Ontario?The increased acreage of genetically engineered (GE) crops planted in Ontario has not led to an increase in herbicide resistant weeds according to results from the University of Guelph’s testing laboratory. Table 1 summarizes the number of species confirmed as resistant to common herbicides used in Ontario over the past 40 years. There are currently fewer species resistant to glyphosate,…
Mike Cowbrough October 14, 2016 11289 Comments Off on Should 2,4-D be used to control weeds in emerged winter wheat during the fall?Co-written by Joanna Follings, Cereal Specialist Should you use 2,4-D to emerged wheat in the fall to control weeds? The short answer is no. First, the label clearly states under the “Application Timing” section: “Do not apply to seedling winter cereals in the fall.” Second, there are other labelled and less injurious herbicide options that provide equivalent or better control of…
Effective control of common burdock doesn’t happen overnight and is most successful when you can control new seedlings in the spring followed by controlling any larger first year plants in the fall so that they don’t overwinter, flower and disperse new seed the following year . Common burdock (Arctium minus) is a biennial that reproduces only by seed. Following seed germination…