PRACTICES

Managing barnyardgrass in rice with a season-long herbicide program

Weed pressure isn’t new to rice growers. Barnyardgrass, in particular, remains one of the most troublesome weeds across rice production systems, and herbicide resistance continues to increase the challenge.

“We’re running out of postemergence options for barnyardgrass,” says Mallory Scott, field market development specialist for Valent U.S.A. “But we have trusted Bolero® Herbicide.”

Bolero® Herbicide fits conventional drill-seeded, water-seeded and Clearfield® rice systems and provides residual control — key for managing yield-impacting weeds.

Frank Carey, senior manager of field research and development for Valent U.S.A., compares barnyardgrass to Palmer amaranth in row crops. He notes that this highly competitive weed has developed resistance to multiple modes of action, making management more difficult.

Applying Bolero as a delayed preemergence herbicide three to five days after planting can help improve barnyardgrass control.

“Delayed preemergence applications are made after planting, once the seed has imbibed moisture and begun germination,” Scott explains. “It may not be visible above ground yet, but applying Bolero at this timing can significantly improve control.”

Regardless of application timing — preemergence, delayed preemergence or postemergence — adequate soil moisture is essential for optimum herbicide performance.

“It doesn’t need to be saturated, but soil moisture must be maintained for consistent control,” Scott adds.

Broad-spectrum control beyond grasses

One key advantage of Bolero is its broad-spectrum activity. In addition to grasses like barnyardgrass, it also helps control annual sedges such as rice flatsedge, as well as certain small-seeded broadleaf weeds and aquatic species.

Postemergence options

For postemergence control, Regiment® Herbicide provides effective control of barnyardgrass and rice flatsedge.

“When barnyardgrass is small, you have more control options,” Carey says. “But once it reaches the fourth leaf stage, options become limited — and by tillering, Regiment may be your best option.”

“It may be small when you schedule an application, but delays can allow it to advance multiple growth stages,” Scott adds.

Strengthen your program with residual control

To improve overall weed control, Scott recommends incorporating multiple herbicides into your program. For growers managing sedges and broadleaf weeds, League® Herbicide is an effective addition.

Adding League to a preemergence tank mix helps control early-season weed competition from sedges and small-seeded broadleaves.

“League is an ALS mode of action, but when applied preemergence, it provides unique control compared to other ALS products,” Scott says.

League also offers control of hemp sesbania (coffeebean or indigo) and provides strong residual activity.

“Its strength is in residual control of sedges and broadleaf weeds, along with some postemergence activity,” Carey adds.

To learn more about Valent rice herbicide solutions, visit the rice products page or contact a Valent sales representative.

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