Annual ryegrass (Lolium multiflorum) is the most damaging weed in soft red winter wheat in Northeast Texas. Annual losses from this pest run in the millions of dollars. Over the past two years, there has been success controlling resistant ryegrass with a two-step herbicide program of Axiom (delayed preemergence to spike) followed by Axial XL (2-3 tiller ryegrass). Click on the photo below to access the full report and two-step program directions.[ezcol_1half]
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Two Step Herbicide Program
In addition to Axiom, two additional herbicides labeled to control resistant ryegrass in winter wheat, Zidua and Anthem Flex are available. Both contain the active ingredient, pyroxasulfone, and are very effective in controlling herbicide resistant annual ryegrass. None of these products should be sprayed on unsprouted wheat seed, but all of these materials can be sprayed as a delayed preemergence (after the wheat is sprouted but before it emerges) for best results. Later applications (up to 1-2 leaf ryegrass) can also be effective, but control is not quite as consistent as the delayed preemergence applications. Of the three products, Axiom is probably the best choiceas a standalone on 1-2 leaf ryegrass, as it contains a low rate of metribuzin, which will provide some burn down activity on the emerged ryegrass. We have had some promising results tank mixing metribuzin with Zidua and Anthem Flex to enhance the postemergence ryegrass control, but do not have enough data to recommend these tank mixes in 2014.
Suggested use rates of these products as a delayed preemergence application on the silt and clay loam soils of northeast Texas are as follows. Always read the label before applying any of these materials.
When used according to label specifications, Axiom, Zidua, and Anthem Flex should provide 80 to 95% control of resistant ryegrass. Axial XL can them be used to control the remaining ryegrass plants that “escape” the early treatments. Axial XL should be applied to ryegrass when it is in the two to three tiller stage of development, which generally occurs in early
to mid-January in northeast Texas.
Growers will likely see a few ryegrass plants survive this two- step treatment. However, the ryegrass escapes will be suppressed by the wheat crop, and are not visible until after the wheat is headed. Our research has shown these late emerging ryegrass plants are not competitive, and do not significantly reduce grain yields.
The following varieties have shown good tolerance to Axiom and pyroxasulfone:
USG 3555, USG 3295, USG 3251, Syngenta Magnolia, Syngenta Coker 9553, Syngenta Oakes, Syngenta Jackpot, Terral TV 8525, Terral TV 8861, Pioneer 25R30, Pioneer 25R40, and Pioneer 25R47.[/ezcol_1half_end]
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