Fluroxypyr Expansion Here to Stay, Requires Stewardship
Fluroxypyr is an important Group 4 herbicide active ingredient that was introduced in the early 1980s. Initially marketed as Starane by Dow, this active ingredient has been widely used in cereals and grass crops due to its crop safety, suitability for mixtures, and its high level of activity on kochia.
In the U.S., fluroxypyr is labeled on wheat, barley, corn, grain sorghum, and pastures. A testimony to its flexibility, fluroxypyr is found in premixes with most of the popular grass and broadleaf herbicides used in wheat. Fluroxypyr also enhances the efficacy of broadleaf herbicide mixtures when targeting weeds such as sericea lespedeza and dogfennel in pasture, as well as clover and plantain in turfgrass.
Kochia continues to be among the most difficult broadleaf weeds in the Plains and Prairie regions of the U.S. and Canada, and there are relatively few effective kochia herbicides that can be safely used postemergence in wheat. For instance, dicamba, which is very active on kochia, is generally considered too injurious to be used at effective rates for kochia when applied postemergence in wheat.
Bromoxynil is a very effective broadleaf wheat herbicide, but due to its contact nature, requires that kochia and other weeds be sprayed when they are relatively small. The systematic nature of fluroxypyr has made it a valuable tool for wheat growers managing kochia, as they are often faced with treating expansive fields where it can be difficult to make timely applications when weeds are small.
The issue is pervasive as kochia, which is a common weed from the panhandle of Texas through the U.S. Plains, continuing well north into the prairie provinces of Canada. While it has historically been a problem in wheat growing geographies, it also infests western corn and soybean production areas. Similarly, the primary use of fluroxypyr has been in small grains, although more recently it has become an important tool in grain sorghum, field corn, and fallow geographies where kochia is found.
The expanse of kochia and importance of fluroxypyr is reflected in recent market data showing that the value of fluroxypyr based herbicide applications has increased from 27% from 2020 to 2022. Total retail sales of herbicides containing fluroxypyr were up more than 14% this year as of September 2023. Similarly, import records for fluroxypyr show very strong growth in the past five years, climbing more than 400%.
Given the importance of fluroxypyr for farmers in the U.S. and Canada, product stewardship and resistance management will be critical. Kochia populations resistant to fluroxypyr have been identified in wheat growing areas of both the U.S. and Canada. The emergence of fluroxypyr-resistant biotypes of kochia joins the growth of kochia populations resistant to ALS, glyphosate, and dicamba as well.
While a boom in fluroxypyr applications is evident, it’s a caution as well. Utilizing effective premixes and tank mixtures, maintaining correct application rates and timings, and rotating and utilizing new chemistries, such as Duplosan* (dichlorprop-p) from Nufarm, to help address weed resistance and maintain the efficacy and value of fluroxypyr.
Some of the more common herbicide mixtures that contain fluroxypyr.
| Product | Manufacturer | Active Ingredients |
| Axial Star | Syngenta | Fluroxypyr + pinoxaden |
| Huskie FX | Bayer | Fluroxypyr + pyrasulfatole + bromoxynil |
| WideMatch / Truslate | Corteva / Nufarm | Fluroxypyr + clopyralid |
| Starane NXT | Corteva | Fluroxypyr + bromoxynil |
| Scorch | Nufarm | Fluroxypyr + dicamba + 2,4-D |
| Carnivore / Cleansweep M | Winfield United / Nufarm | Fluroxypyr + bromoxynil + MCPA |
| Kochiavore / Cleansweep D | Winfield United / Nufarm | Fluroxypyr + bromoxynil + 2,4-D |
| GoldSky | Corteva | Fluroxypyr + florasulam + pyroxsulam |
*Duplosan is a trademark of Nufarm and registered for use in Canada for small grains and preplant use, and pending registration in US for small grains, preplant and fallow.
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