Recent rains in parts of Kansas have caused weeds to begin growing rapidly, and in some cases overtaking fields of wheat that are thin and very short. No one wants to spend extra money on a below-average crop, but these weeds can make harvest very difficult.
There are several herbicide options producers can use as pre-harvest aids in wheat. There are differences in how quickly they act to control the weeds, the interval requirement between application and grain harvest, and the level or length of control achieved. All of them will require very good coverage to be effective, meaning a high gallonage spray volume should be used.
The various options include:
|
Product and rate |
Advantages |
Disadvantages |
Comments |
|
Aim EC (1 to 2 oz) |
Acts quickly, usually within 3 days. Short waiting interval before harvest – 3 days. |
Controls only broadleaf weeds. Regrowth of weeds may occur after 2-3 weeks or more, depending on the rate used. |
Apply after wheat is mature. Always apply with 1% v/v crop oil concentrate in a minimum spray volume of 5 gal/acre for aerial application and 10 gal/acre for ground applications. Do not apply more than 2 oz of Aim during the growing season. |
|
Dicamba (0.5 pt) + 2,4-D (0.5 to 1 qt of 4 lb/gal) |
Broad-spectrum broadleaf weed control. |
A waiting period of 10 to 14 days is required before harvest. Acts slowly to kill the weeds. Controls only broadleaf weeds. |
Apply when the wheat is in the hard dough stage and green color is gone from nodes the stem. Do not allow grazing or use feed from treated area. |
|
Glyphosate (1 to 2 pt of 3 lb ae/gal) + 2,4-D (1 to 2 pt) |
Provides control of both grasses and susceptible broadleaf weeds. |
Acts slowly. May take up to 2 weeks to completely kill weeds and grasses. Cannot harvest grain until 7 days after application. |
Apply when wheat is in the hard dough stage (30% or less grain moisture). Consult label for recommended adjuvants. Do not feed treated straw or permit dairy animals or meat animals being finished for slaughter to graze treated fields within 2 weeks after treatment. Not recommended for wheat being harvested for use as seed. |
|
Metsulfuron (0.1 oz) + 2,4-D (0.5 to 2 pt of 4 lb/gal) |
Provides control of susceptible broadleaf weeds. |
Acts slowly. Cannot harvest grain until 10 days after application. Controls only broadleaf weeds. |
Apply when wheat is in the dough stage. Always apply with a nonionic surfactant at 0.25 to 0.5% v/v. Do not use on soils with a pH greater than 7.9. Weeds growing under limited moisture may not be controlled. Do not use treated straw for livestock feed. |
|
2,4-D LVE |
Provides control of susceptible broadleaf weeds. |
Acts slowly. Weak on kochia and wild buckwheat. |
Apply when wheat is in the hard dough stage to control large, actively growing broadleaf weeds. Weeds under drought stress may not be controlled. Do not use treated straw for livestock feed. Consult label of individual products for preharvest interval requirement. |
There are several herbicide options producers can use as pre-harvest aids in wheat. It is especially important to know pre-harvest interval requirements and how treated wheat can be used after application.
Dallas Peterson, Weed Management Specialist
dpeterso@ksu.edu
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