Australia - New herbicide option to control Caltrop in sorghum

Sorghum growers now have access to an innovative herbicide proven to control Caltrop (Yellow vine) (Tribulus terrestris) as a post emergent option.

Corteva Agriscience have registered Ubeniq^® Rinskor^® active herbicide in sorghum as a tank mix partner to specifically control Caltrop.

Caltrop has become a major issue for growers with seeds that remain dormant in the soil for extended periods of time and germinate with summer rainfall. It has many names in different regions of Australia eg. Yellow vine, Cat’s head, puncture vine or Goat’s head, having distinctive yellow flowers and sharp burrs that form within three to five weeks after emergence.  The burrs can attach to tyres and stock and move around paddocks, farms and districts reducing production efficiency in many situations.

Corteva Agriscience Marketing Director, Dan Dixon, said the company has marketed Starane^® Advanced (fluroxypyr) herbicide into the Australian sorghum market for years, but had noted the challenges growers were having with Caltrop control.

Dan Dixon next to a Ubeniq trial at Breeza Field Station, NSW

″Over the past three decades Starane Advanced has become the standard for post emergent weed control in grain and forage sorghum.″

Starane Advanced has a wide range of broadleaf weeds on the label.  ″Generally, Starane has been mixed with Atrazine for broad spectrum control of problem weeds in sorghum crops,″ Mr Dixon said. ″Unfortunately, in recent years Caltrop has been more difficult to control with the Starane Advanced mixtures, so we set about looking for a solution.″

He said Ubeniq^® Rinskor^® active herbicide had been registered in Australia since 2018 for post-emergent weed control in rice. Mr Dixon said ″Ubeniq is based on Rinskor, which is a new arylpicolinate active ingredient in the chemical class of synthetic auxin (Group 4) herbicides.

It is very active at low use rates and has an extremely attractive environmental profile - winning the US EPA Green chemistry award in 2018.″

Trials were conducted over a six-year period to determine the ability of Ubeniq to control summer weeds, selectivity to sorghum and suitability as a tank mix partner with Starane Advanced and other products.

″The trials demonstrated the ability of Ubeniq to provide outstanding control of Caltrop in sorghum crops,″ Mr Dixon said.

″Corteva is really pleased to provide a solution for Caltrop as a tank mix partner with post-emergent herbicides that are currently used in sorghum crops.″

Ubeniq 25 mL/ha + Starane Advanced 300 mL/ha + Hasten, 13 days after application in forage sorghum, Pittsworth, 2020

″Ubeniq has proven to be safe across sorghum varieties, and it also worked particularly well as a tank mix partner.″

The addition of Ubeniq at a label rate of just 25 mL per hectare, provides excellent control of Caltrop and included the benefits derived from the existing herbicides.  ″It is an excellent mixing partner for Starane Advanced herbicide, particularly for fast control of Caltrop and seems to be adding to the speed of control of other weeds.″

In sorghum, Ubeniq can be tank mixed with Starane^® Advanced and Hasten^® Spray Adjuvant. In paddocks or areas where growers can use atrazine this can also be added to the mix to further strengthen the overall control.″

″With an extremely short grazing withholding period of just 3 days, this could be an excellent option for forage sorghum growers looking to control caltrop and prevent any livestock becoming lame.″

In most situations growers will have no issues with rotational cropping to the full range of winter crops following the use of Ubeniq in sorghum.

Sorghum Trial at Breeza Field Station, NSW

At the recommended use rate, the maximum re-cropping interval is just two months (with a minimum 75 mm rainfall requirement) to crops such as canola, chickpeas and field peas, with a four week plant back to wheat, barley, oats, triticale and ryegrass.

Ubeniq Rinskor active herbicide has also recently been registered to control Navua sedge (Cyperus aromaticus) in pastures.

Navua sedge has been an issue for graziers in northern Queensland for many decades and Ubeniq provides an opportunity to control the weed to improve pasture production and stocking rates.