Is now the time to control mustard weeds in your wheat fields?
Sandra Wick, Crop Production Agent
Too often producers do not notice mustard weeds in their wheat fields until the mustards start to bloom in the spring with that yellow or lavender color. As a result, producers often don’t think about control until that time. Although it is still possible to get some control at that time with herbicides, mustards are much more difficult to control at that stage and often have already reduced wheat yields by then. The following is information on managing mustard weeds in your wheat.
To keep yield losses to a minimum, mustards should be controlled by late winter or very early spring, before the plants begin to bolt, or stems elongate according to Dallas Peterson, K-State Research and Extension Weed specialist. If winter annual broadleaf weeds are present in the fall, they can be controlled with any number of ALS-inhibiting herbicides, including Ally, Amber, Finesse, Rave, or PowerFlex. Other non-ALS herbicides such as Huskie, Quelex, 2,4-D, or MCPA can also provide good control of most mustards if the weeds are at the right stage of growth and actively growing, and if the wheat is at the correct growth stage.
There are several different species of the mustard weed family so it is important to first and foremost identify what specie is present so the most effective herbicide can be used. Flixweed and tansy mustard should be treated when they are no larger than two to three inches across and two to three inches tall. As these plants become larger, the control decreases dramatically. Field pennycress is easier to control than tansy mustard or flixweed. Wheat should be fully tillered before applying 2,4-D or tillering will be inhibited and wheat yields may be decreased.
Most ALS-inhibiting herbicides control winter annual mustards very well, although there are populations of some mustards in Kansas that are ALS-resistant and cannot be controlled by these products. So what options are available? The best approach is to use other herbicides such as 2,4-D, MCPA, or Huskie or in a tank-mix with the ALS herbicides. None of these herbicides have much residual control, so the majority of weeds need to be emerged and actively growing at the time of treatment.
Quelex is a new product from Dow AgroSciences that is a premix of a short-lived ALS herbicide and a new auxin-type herbicide. It generally can provide good control of most mustard species and should be applied from the 2-leaf up to flag leaf emergence growth stages of wheat. Also remember to use it in combination with a nonionic surfactant or oil concentrate.
Some producers commonly apply ALS herbicides with fertilizer in January or February. Unfortunately, MCPA, 2,4-D, and Huskie are most effective when applied to actively growing weeds, so application when weeds are dormant may not provide good control. As a result, if an ALS-inhibitor tank-mix with one of these herbicides is applied to dormant ALS-resistant mustards in the winter, poor control could occur.
Producers should watch for cases of poor control, and consider alternative herbicides or herbicide tank-mixes to help prevent or manage ALS-resistant weeds. Crop rotation with corn, grain sorghum or soybeans is a good way of managing mustards as long as they are controlled in the spring prior to producing seed.
The “2018 K-State Research and Extension Chemical Weed Control” publication is available online at http://bit.ly/2yqhFWZ. The publication will also be available, in print at no cost, after the first of the year at any of our Post Rock Extension District Offices. The publication is an excellent resource that provides the effectiveness of different herbicides for each of our major crops.
For more information on “weed control”, stop by or call me at any office of our Post Rock Extension District in Beloit, Lincoln, Mankato, Osborne or Smith Center.
Post Rock Extension District of K-State Research and Extension serves Jewell, Lincoln, Mitchell, Osborne, and Smith counties. Sandra may be contacted at swick@ksu.edu or by calling Smith Center, 282-6823, Beloit 738-3597, Lincoln 524-4432, Mankato 378-3174, or Osborne 346-2521. Join us on Facebook at “Post Rock Extension” along with our blog site at “postrockextension.blogspot.com. Also remember our website is www.postrock.ksu.edu and my twitter account is @PRDcrops.
To keep yield losses to a minimum, mustards should be controlled by late winter or very early spring, before the plants begin to bolt, or stems elongate according to Dallas Peterson, K-State Research and Extension Weed specialist. If winter annual broadleaf weeds are present in the fall, they can be controlled with any number of ALS-inhibiting herbicides, including Ally, Amber, Finesse, Rave, or PowerFlex. Other non-ALS herbicides such as Huskie, Quelex, 2,4-D, or MCPA can also provide good control of most mustards if the weeds are at the right stage of growth and actively growing, and if the wheat is at the correct growth stage.
There are several different species of the mustard weed family so it is important to first and foremost identify what specie is present so the most effective herbicide can be used. Flixweed and tansy mustard should be treated when they are no larger than two to three inches across and two to three inches tall. As these plants become larger, the control decreases dramatically. Field pennycress is easier to control than tansy mustard or flixweed. Wheat should be fully tillered before applying 2,4-D or tillering will be inhibited and wheat yields may be decreased.
Most ALS-inhibiting herbicides control winter annual mustards very well, although there are populations of some mustards in Kansas that are ALS-resistant and cannot be controlled by these products. So what options are available? The best approach is to use other herbicides such as 2,4-D, MCPA, or Huskie or in a tank-mix with the ALS herbicides. None of these herbicides have much residual control, so the majority of weeds need to be emerged and actively growing at the time of treatment.
Quelex is a new product from Dow AgroSciences that is a premix of a short-lived ALS herbicide and a new auxin-type herbicide. It generally can provide good control of most mustard species and should be applied from the 2-leaf up to flag leaf emergence growth stages of wheat. Also remember to use it in combination with a nonionic surfactant or oil concentrate.
Some producers commonly apply ALS herbicides with fertilizer in January or February. Unfortunately, MCPA, 2,4-D, and Huskie are most effective when applied to actively growing weeds, so application when weeds are dormant may not provide good control. As a result, if an ALS-inhibitor tank-mix with one of these herbicides is applied to dormant ALS-resistant mustards in the winter, poor control could occur.
Producers should watch for cases of poor control, and consider alternative herbicides or herbicide tank-mixes to help prevent or manage ALS-resistant weeds. Crop rotation with corn, grain sorghum or soybeans is a good way of managing mustards as long as they are controlled in the spring prior to producing seed. The “2018 K-State Research and Extension Chemical Weed Control” publication is available online at http://bit.ly/2yqhFWZ. The publication will also be available, in print at no cost, after the first of the year at any of our Post Rock Extension District Offices. The publication is an excellent resource that provides the effectiveness of different herbicides for each of our major crops.
For more information on “weed control”, stop by or call me at any office of our Post Rock Extension District in Beloit, Lincoln, Mankato, Osborne or Smith Center.
Post Rock Extension District of K-State Research and Extension serves Jewell, Lincoln, Mitchell, Osborne, and Smith counties. Sandra may be contacted at swick@ksu.edu or by calling Smith Center, 282-6823, Beloit 738-3597, Lincoln 524-4432, Mankato 378-3174, or Osborne 346-2521. Join us on Facebook at “Post Rock Extension” along with our blog site at “postrockextension.blogspot.com. Also remember our website is www.postrock.ksu.edu and my twitter account is @PRDcrops.
