Rice production has been blessed in the past 20 to 25 years with a large number of herbicides labeled for use in rice, and several new materials gained labeled in 2017. Below is a brief discussion of each of the new products.
Loyant – Dow
In early October, Dow AgroSciences received a label for Loyant. The active ingredient in Loyant is florpyrauxifen-benzyl. Loyant can be applied to both drill- and water-seeded rice in the two-leaf stage at a rate of 1 pint per acre.
A methylated seed oil (MSO) at 0.5 pints per acre is required. Wait at least 14 days between Loyant applications, and do not apply more than 2 pints per acre per year. Loyant controls most broadleaf and sedge weeds found in rice, including many aquatic broadleaf weeds. Loyant has no activity on Texasweed.
Loyant has activity on small barnyardgrass, broadleaf signalgrass, junglerice and Amazon sprangletop no larger than the three- to five-leaf stage. Apply to small, actively growing weeds. If the flood is not present at application, establish permanent flood within three days. If the permanent flood is present at application, make sure weeds are exposed 70 percent above water level, and wait three hours before adding more water. Loyant has no residual activity on weeds that have yet to emerge.
Avoid the use of Loyant on freshly cut or leveled ground, except water-leveled fields. Loyant has auxin activity similar to 2,4-D or Grandstand. Avoid drift to neighboring soybeans and other broadleaf crops.
Provisia – BASF
BASF received a label for the Provisia herbicide in the spring of 2017. The active ingredient in Provisia is quizalofop. Apply this herbicide only to Provisia rice varieties. Provisia controls red rice, weedy rice, and annual and perennial grass weeds commonly found in rice fields.
The first application to Provisia rice should be applied at 13 to 18 ounces per acre. Adequate soil moisture is required for optimum herbicide activity. A second application of Provisia must be applied prior to panicle initiation. Do not apply more than 31 ounces per acre per year. Applications of Provisia to Provisia rice can cause injury, and it is usually in the form of yellow foliage – often referred to as a “yellow flash.” Avoid overlapping when applying Provisia. When Provisia is mixed with other herbicides, antagonism can occur. Refer to the Provisia label for approved mixtures.
RiceOne – RiceCo
In the spring of 2017, RiceCo received a label for RiceOne. This new herbicide is a prepackaged mixture of clomazone plus pendimethalin. Due to the presence of pendimethalin in the mixture, this herbicide cannot be applied as a preemergence treatment immediately after planting. This herbicide mixture controls barnyardgrass, broadleaf signalgrass, Amazon sprangletop and fall panicum prior to weed emergence.
RiceOne also has activity on many small-seeded broadleaf weeds when applied prior to weed emergence. RiceOne may be applied as a surface broadcast application as a delayed preemergence application or as an early postemergence treatment to rice. Early postemergence applications will need another herbicide to control emerged weeds. RiceOne rates are soil texture dependent. So, refer to the product label for proper rates. Do not apply RiceOne to water-seeded rice.
Gambit – Gowan
In early October, Gowan received a label for Gambit. This new herbicide is a prepackaged mixture of halosulfuron plus prosulfuron. Gambit should be applied at a rate of 1 to 2 ounces per acre under dry or flooded conditions.
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Do not apply more than 2 ounces per acre per year. Refer to label for approved adjuvants. Gambit controls broadleaf weeds and sedges. Apply to actively growing broadleaf weeds in the one- to three-leaf stage, and sedges in the three- to six-leaf stage.
If applied under flooded conditions, weeds should be exposed above the flood 70 to 80 percent. Do not flush or flood within 24 hours after application. Hold flood water for 14 days after application, and do not apply within 48 days of harvest.
All of these new herbicides can be beneficial in Louisiana rice production. As always, use a well-designed weed control program with multiple modes of action by taking advantages of residual herbicides such as RiceOne followed by post-emergence herbicides such as Gambit, Loyant and Provisia.