Farm Progress

Arkansas rice First treatment sets up weed control

Ford Baldwin

April 20, 2007

3 Min Read

I wrote in an earlier article that the only thing we knew about this year, going in, is it would be different. Boy has it ever been different.

We went from an exceptionally warm March to a hard freeze in early April. I hope we are getting into more normal weather.

On much of the rice that has been planted, there have been chances to apply and activate Command.

I hope everyone has taken the opportunity to get this done.

I will focus now on the early postemergence part of the season. The first postemergence treatment often sets the stage for how the remainder of the weed control season will go.

When you get emerged grasses to the two- to three-leaf stage, you have to kill them right then.

While we have herbicides capable of killing larger grass, too many things can go wrong when you consistently get into situations with larger grass.

Make it a point to kill the first flush of grass in conventional rice or the first flush of red rice in Clearfield rice when it is two- to three-leaf. You will not mess up spraying too early.

For early postemergence grass control, I usually choose between two basic herbicides — Ricestar HT or a propanil product such as Super Wham or Duet.

Frequently one herbicide steps up during a particular season and exceeds expectations on performance or acres treated or both.

Last year that herbicide was Ricestar HT. During much of the early postemergence season it was cool and that really fit Ricestar HT in a lot of situations where propanil may have otherwise been used.

The 24-C registration for Ricestar HT that allows rates up to 24 ounces to be used has made it an excellent grass herbicide when used alone or tank-mixed with Facet, Quinstar of Command. I prefer the tank mixes to get both postemergence and residual control.

Situations that favor Ricestar HT over propanil are cooler temperatures, propanil-resistant barnyardgrass and sprangletop, and in some cases just larger grasses in general.

Last year propanil sales were down considerably. This was due in part to so many of the early situations favoring Ricestar HT and also due to the large increase in Clearfield acres.

Because a lot of newer herbicides entered the rice market over the past 10 years, we will never have the majority of the rice acres treated with two applications of propanil as once was the standard. However, I would remind you not to forget about propanil as a rice herbicide.

We have made strides in barnyardgrass control with some of the newer herbicides, but a lot of the increase in broadleaf weed pressure we are seeing is due to the decreased use of propanil.

We often think of propanil as a grass herbicide and forget how much broadleaf activity it has.

A significant portion of Arkansas this year has increased regulations on 2,4-D. When you take 2,4-D out of the broadleaf program you must think about broadleaf control over the entire season as opposed to just at midseason.

In situations where the weed spectrum is a mixture of small grasses and broadleaf weeds, treatments like Super Wham plus Command, Facet or Quinstar are excellent.

If you use an alternative treatment early, Super Wham or Duet plus a broadleaf herbicide applied just prior to flooding can head off a lot of broadleaf problems later. This is true both in conventional and Clearfield rice.

We are fortunate that there are a lot of excellent herbicide choices in rice.

The best choice depends on the situation. Sometimes the situation can change overnight.

Keep your options open but keep your timing early. Feel free to call with your individual situation if I can help.

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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