Spring herbicide applications in wheat
Barton County Extension Agent
Residual herbicides applied to wheat in early spring can provide good weed control for several weeks after harvest, in some situations. This strategy should only be used in a wheat/row crop/fallow, wheat/fallow, or continuous wheat cropping system.
The application timing and length of residual activity depends on the herbicide being used, the weeds present, soil pH level, and moisture conditions. The residual activity from Amber, Finesse, Glean, and Rave will be longer on soils with higher pH levels, and where conditions have been dry. Rave (a premix of dicamba and the active ingredient in Amber herbicide) can be applied up until the start of jointing. Amber, Finesse, and Glean can be applied slightly later, until early jointing.
These herbicides will provide residual control of many winter annual and summer annual broadleaf weeds, but not ALS-resistant weeds. The residual activity means that row crops cannot be double-cropped after the wheat. In a wheat/row crop/fallow system, there is usually enough time to allow grain sorghum and soybeans to be safely planted the following spring. Producers have to be more careful when planting corn the following spring. Corn is more sensitive to sulfonylurea herbicide carryover, and it is planted earlier in the spring than grain sorghum and soybeans. Consult the respective herbicide labels for specific crop rotation guidelines.