Evaluating Herbicide Efficacy in Flax
Helen Booker, Saskatchewan Crop Development Centre
The purpose of this project is –
1) To compare efficacy of standard herbicide (Authority) treatments to experimental herbicide (Armezon) treatments in controlling weeds in flax.
2) To determine any safety concerns from the use of herbicide combinations.
Interestingly there were no flax injuries with Authority + Mextrol option but Armezon in combination with Mextrol caused injuries. Based on these preliminary findings, this combination should be avoided in real farm situations unless if further studies with reduced applications rates of Mextrol can prove otherwise. Armezon on its own did not seem to show crop injury, but it stunted the height of flax, which could reduce seed yield. Arborg was the only site that showed yield loss based on herbicide use in general. At this site, Armezon showed yield loss both in sole use, and in combination with Mextrol. The study will be conducted again in 2021 before recommendations can be made available for registration of Armezon in flax. There might be need to consider reducing Mextrol application rates when used in combination with Armezon in order to address crop injury concerns.
Flax (Linum usitatissimum) is an important crop known for its value in food and fiber industrial markets around the world. However, flax has a low competitive ability with weeds compared to other crops. Various weed management strategies that include; competitive varieties, early seeding, increased seeding rates and the use of pre- and post-emergence herbicides can help to control weeds and reduce yield losses than using only one control method (Kurtenbach et al., 2019). Pre-emergence weed control is crucial in flax to reduce yield loss since flax is a weak competitor with weeds (Berglund and Zollinger, 2007).
Post-emergence weed control, if done timely, usually results in better weed control and allow more time for flax recovery from possible herbicide injury. There is currently a challenge in herbicide options for flax as a result of herbicide resistance. Furthermore, herbicide injury concerns after the use of different herbicide combinations need to be examined. There is need to investigate possible alternative options, herbicide combinations and timings of application for control of both broad leaf weeds and grasses.
Armezon® herbicide, which is classified as Group 27, is an effective tank-mix option that is currently registered as a post-emergence herbicide for the control of tough broad leaf weeds and grasses in corn and has potential for use in flax for control of Group 1 resistant grasses (Table 6). Currently, the herbicide is not registered for use in flax but extensive field trials can provide data for registration. Therefore, this study is evaluating several herbicides including Authority, Mextrol, Koril, Select and experimental Armezon used alone or tank mixed with compatible herbicides to see their effectiveness in weed control and protecting yield losses. The study also aims to assess any safety concerns with the use of different herbicide mixes in flax.