Author: Mike Cowbrough

Mike Cowbrough

Areas of Focus • Weed management systems for field crops • Editor of Guide to Weed Control Publication 75

Mixing “ATS” with herbicides: The importance of a “jar test”

An attempted jar test mixing of Liberty 200 SN with ATS as a carrier, resulting in unacceptable mixing.
Mike CowbroughMike Cowbrough May 3, 2020 542 Comments Off on Mixing “ATS” with herbicides: The importance of a “jar test”
Weeds

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…

Controlling Scentless Chamomile with Herbicides

Mike CowbroughMike Cowbrough April 1, 2020 536 Comments Off on Controlling Scentless Chamomile with Herbicides
Weeds

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…

Killing off Roundup Ready Alfalfa

Mike CowbroughMike Cowbrough November 21, 2019 1186 Comments Off on Killing off Roundup Ready Alfalfa
Forages

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…

What’s Working on the Farm? Practical Solutions for Problem Weeds

Mike CowbroughMike Cowbrough March 22, 2019 2142 Comments Off on What’s Working on the Farm? Practical Solutions for Problem Weeds
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…

Managing Glyphosate Resistant Canada Fleabane with Cover Crops and Tillage

Mike CowbroughMike Cowbrough November 20, 2018 2135 Comments Off on Managing Glyphosate Resistant Canada Fleabane with Cover Crops and Tillage
Weeds

My 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…

Guide to Weed Control in Field Crops – Pub 75A

Mike CowbroughMike Cowbrough May 17, 2018 5347 Comments Off on Guide to Weed Control in Field Crops – Pub 75A
Weeds

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”

Crop response to herbicides applied prior to and after emergence.

Mike CowbroughMike Cowbrough August 8, 2017 2861 Comments Off on Crop response to herbicides applied prior to and after emergence.
Uncategorized

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…

Problem Weed Guide

Mike CowbroughMike Cowbrough March 20, 2017 11332 Comments Off on Problem Weed Guide
Weeds

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…

Has the adoption of genetically engineered (GE) crops resulted in more herbicide resistant weeds in Ontario?

Mike CowbroughMike Cowbrough December 5, 2016 5953 Comments Off on Has the adoption of genetically engineered (GE) crops resulted in more herbicide resistant weeds in Ontario?
Weeds

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,…

Should 2,4-D be used to control weeds in emerged winter wheat during the fall?

Mike CowbroughMike Cowbrough October 14, 2016 10742 Comments Off on Should 2,4-D be used to control weeds in emerged winter wheat during the fall?
Weeds

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…

Controlling common burdock

Mike CowbroughMike Cowbrough October 11, 2016 10537 Comments Off on Controlling common burdock
Weeds

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…

Farmers are reducing weed seed return after cereal harvest

Mike CowbroughMike Cowbrough September 23, 2016 4625 Comments Off on Farmers are reducing weed seed return after cereal harvest
Cover Crops

I was driving down a long country road and noticed that two large fields, where winter wheat was harvested almost eight weeks ago,  had a beautiful thick canopy of oats. It wasn’t long until I came across a field that was left fallow, that it became clear why so many farmers had chosen to plant an oat cover crop. There was…

Weed ID Guide for Ontario Crops

Mike CowbroughMike Cowbrough September 19, 2016 15959 Comments Off on Weed ID Guide for Ontario Crops
Weeds

Featuring over 120 species commonly found in and around agricultural fields, the Weed ID Guide for Ontario Crops is now available in the following formats. ePub format (124 MB file for Kindle, iBooks and other e-reader apps): click to download .pdf format (8 mb file): click to download print ready .pdf (141 mb file): click to download Print Copy (printing and…

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