Farm Progress

In rice fields: Emerging grass guides weed control

Ford Baldwin

April 18, 2003

3 Min Read

Right after I had written last week's article, several more products — Cornerstone (glyphosate), Glyphomax, Newpath, and Touchdown — were approved and added to the 24-C aerial label for Command.

After the early-April rain caught farmers with rice planted and no Command or Newpath out, several asked, “What do I do now?” I hope that will not be the last rain we get during the planting season; others likely will get caught in the same situation.

Several wanted to know if they applied the Command to wet soil, would it activate without a flush. My recommendation is to apply the Command to the wet soil as soon as the surface water is off. It usually will activate some on the wet soil. This is another reason the option for applying Command by air is nice. If you were rained out without levees up and you want Command on the levees, too, you can wait until it dries, pull the levees and then apply the Command.

In these situations, look closely for emerged grass and if it is there add an appropriate tank mix partner.

When you apply the Command after the soil dries, it will need to be activated just as if it were applied right after planting.

You really can not mess up about any way you do it as long as you activate the Command (if needed) and you watch for emerged grass at the time of application.

Regardless of whether you apply Command to wet or dry soil, or whether it has been active for a while and it is now getting dry, the emerging grass will tell you what to do. As long as the emerging grass is coming out of the ground pink or white, it is active. At the first sign of tiny green grass emerging, flush it immediately.

In a couple of calls where growers planting Clearfield rice were rained out before they got the pre-emergence treatment out, my recommendation was to wait and apply the first Newpath treatment at around the two-leaf rice stage if the variety was CL161 or CLXL8. I am simply not a fan of pre-emergence applications (surface applied and not incorporated) of Newpath.

In situations where the first application of Newpath can be incorporated into a good, smooth seedbed, I like the ppi followed by a single postemergence application, the two-shot postemergence program equally well. I much prefer both programs to a program using a pre-emergence application followed by a single postemergence treatment. The reason for this is the uncertainty of getting the pre-emergence treatment properly activated for maximum performance.

The key to the Newpath system is to knock a homerun with however you choose to make the first application so all you are doing with the second application is taking out escapes.

Obviously with CL121 or 141, if you can not incorporate, you have to try to make the pre-emergence treatment work. The beauty of the newer varieties is you never have to consider the pre-emergence treatment.

If incorporation is not an option or you prefer not to, go straight to the two-shot postemergence approach with the new varieties. A program we like really well is to apply Command as a pre-emergence treatment, make the first shot of Newpath at the two-leaf rice stage, and then apply the second shot of Newpath with a broadleaf herbicide just before flooding. You want good soil moisture when you apply the postemergence treatment and some moisture for activation after you apply it.

Ford Baldwin, Practical Weed Consultants. e-mail: [email protected].

About the Author(s)

Ford Baldwin

Practical Weed Consultants

Ford Baldwin served as a weed scientist with the University of Arkansas Cooperative Extension Service from 1974 to 2001. During that time he conducted extensive applied research trials in rice, soybeans, cotton and wheat, and developed weed management recommendations and educational programs for farmers. Since January 2002, Baldwin has been a partner in Practical Weed Consultants with his wife, Tomilea.

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