Cotton: Early Season Management of Weeds

Ayman Mostafa and Bill McCloskey
Watering up and planting to moisture are the two main methods of germinating seed at cotton planting time in Arizona. Many cotton growers in Arizona pre-irrigate their fields before planting cotton, mainly because their soil texture is too light for moisture to be consistent as needed for germination. Unlike planting to moisture, watering up can result in intense early season weed competition and can put greater reliance on selective over-the-top herbicide chemistries.
It should be clear that a preemergence herbicide will never stop the emergence of every single weed seedling in a field. Growers and PCAs usually must still go out and spray a postemergence herbicide to control the escapes so there is an increase in the number of weed control operations. The use of dinitroaniline (DNA or “yellow”) preemergence herbicides at the beginning of the cotton season can provide a foundation for season-long weed management, along with tillage, cultivation and other postemergence herbicides at lay by. Proper utilization of preemergence herbicides can reduce weed density and make other weed control operations more manageable, especially decreasing the pressure on the available effective, selective postemergence control options.
Click Here for a short 1-page piece on the DNA herbicides that might be very useful in managing glyphosate-resistant Palmer Amaranth in Arizona cotton.

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