Google Translate Disclaimer

A number of pages on the Government of Saskatchewan`s web site have been professionally translated in French. These translations are identified by a yellow text box that resembles the link below and can be found in the right hand rail of the page. The home page for French-language content on this site can be found here:

Renseignements en Français

Where an official translation is not available, Google™ Translate can be used. Google™ Translate is a free online language translation service that can translate text and web pages into different languages. Translations are made available to increase access to Government of Saskatchewan content for populations whose first language is not English.

The results of software-based translation do not approach the fluency of a native speaker or possess the skill of a professional translator. The translation should not be considered exact, and may include incorrect or offensive language Government of Saskatchewan does not warrant the accuracy, reliability or timeliness of any information translated by this system. Some files or items cannot be translated, including graphs, photos, and other file formats such as portable document formats (PDFs).

Any person or entities that rely on information obtained from the system does so at his or her own risk. Government of Saskatchewan is not responsible for any damage or issues that may possibly result from using translated website content. If you have any questions about Google™ Translate, please visit: Google™ Translate FAQs.

Post-Harvest Weed Control

By: John Ippolito, P.Ag., Regional Crops Specialist, Kindersley

September 2017

There are always a couple of weed problems that producers feel it may be necessary to control  after harvest if they were not able to do as a pre-harvest practice. This year is no different and two weeds that are definitely on producers’ minds are kochia and Canada thistle.

Kochia may not have been totally controlled through pre-harvest herbicide applications or a portion of the plant remains viable after harvest which may be the case in cereals and oilseeds. There has been research conducted in both Montana and Alberta that studied regrowth of kochia plants and their ability to produce viable seed. The research found that the portions of a kochia plant remaining in the wheat stubble will continue to mature and produce viable seed up until a hard frost occurs. Harvest operations after August 15 in Montana resulted in less viable seed being produced but there was still seed produced. The research in Alberta compared herbicide applications 1 week and 3 weeks after harvest and found that there was not a significant reduction in seed production compared to the untreated check.

These trial results would indicate that there is not a lot of merit for post-harvest herbicide applications specifically to prevent kochia from producing more seed after harvest. For producers wishing to use this practice in west central and southwest Saskatchewan it is important to note that a herbicide mixture including glyphosate and some other herbicide groups may be required.

Canada thistle control after harvest is always an option, but a couple of recommendations must be considered closely. The requirement for regrowth after harvest is likely the biggest concern in 2017. The plants should be allowed to regrow until there is at least 8 inches of new growth prior to application. Glyphosate rates required for post-harvest application are normally recommended to be in the range of 690 to 1,020 grams of active ingredient per acre, which, essentially, is double recommended pre-harvest rates. There is also a requirement for a frost free period after application.

Post-harvest weed control practices are often an option but in the case of 2017 and the weeds involved we may not achieve the desired results until we have a significant change in weather conditions.  For more information on post-harvest weed control operations contact your regional crop specialist or the Agriculture Knowledge Centre at 1-866-457-2377.

We need your feedback to improve Help us improve