Rice Weed Control 101

What About Broadleaf Herbicides In Rice?

Andy Kendig, State Extension Weed Specialist

Printed/Posted with permission of Mid America Farmer Grower

Rice has a number of broadleaf herbicides and rice fields are probably treated for broadleaf and/or aquatic weeds about 50% of the time. You may notice that you only have broadleaf and aquatic weeds in areas where there is no rice. Broadleaves and aquatics love skips and the ditches along levees. Obviously the competition and shading of a good healthy rice crop suppresses broadleaf and aquatic weeds. Also helping with broadleaf control is the fact that most "grass" herbicides are also very good broadleaf herbicides (Command, Prowl and Whip are exceptions). We conduct a broadleaf weed control experiment every year- and very rarely does any treatment beat the old Stam 3 + 3 standard. The same could be said for most other propanil, Facet, or Bolero containing programs. These herbicides will control MOST broadleaf weeds.

Blazer, Basagran and Storm are commonly used. Basagran is good on a number of broadleaf weeds and is also ok if you have some nutsedge or smartweed. Blazer is a tremendous herbicide for hemp sesbania or coffeebean. Obviously, Storm gives you the "best of both worlds".

Grandstand is a good, low-cost broadleaf herbicide. It works best tank mixed with about a quart of Stam and controls hemp sesbania, morningglory and jointvetch or indego. Check the label closely, flooding soon after Grandstand application can injure rice. Also pay attention to the ½" internode cutoff (which is supplied by DD-50 computer programs) You should know that Grandstand is a hormone-type herbicide with a similar mode of action to 2,4-D. However, this herbicide has virtually no volatility and cotton does not have the extreme 2,4-D sensitivity to Grandstand. You still must use common sense and Grandstand shouldn't be flown with wind blowing towards an adjacent cotton or soybean field. However, it will not walk around and find cotton miles away.

Londax is a typical rice herbicide with instructions that change from one use pattern to another. Farmers have typically used Londax to control aquatic weeds, nutsedge and smartweed in the floodwater. More recently, DuPont has been promoting more of a preventative approach, applying Londax preflood. There is are also a herbicides called StamPro and Duet which combine both Stam and Londax. It's hard to know for sure if you'll really need to treat so you might want to save your Londax until problems develop.

Just last year, the corn herbicide "Permit" received a rice registration. It is an excellent option for nutsedge- which is an ongoing problem in rice production. Command and Prowl based programs can make sedge problems worse. While Permit will displace a lot of the Londax that was used for nutsedge, Londax remains the product of choice for control of aquatic-type weeds after rice is flooded. Consequently there is a place for both herbicides in a rice weed control program and DuPont is promoting tank mixtures of the two for both nutsedge and aquatic control.

While broadleaf and aquatic weeds are the exception in drill seeded rice, aquatics are the rule in water seeded rice. During the time when the small rice is establishing itself, there is little shading to stop aquatics. An early Londax application is basically a requirement for water-seeded rice.

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