Two sprays now common for wild radish control

Landmark Carnamah agent Graham Doust, of Doust Agri-Services, said wild radish control remained a widespread problem in the area and most farmers now conceded that two herbicide sprays were required.  “They now do it regardless. They budget for it,’’ Graham said.

He said farms had moved to 70-100% cropping in recent times, with two to three years of wheat followed by canola being a popular rotation, and most farms had some paddocks with bad wild radish populations.

“There had been consistent use of phenoxy herbicide treatments, for example LV Ester and DFF (diflufenican) – and then the use of Jaguar^®.’’  “There is resistance to Group B and F, and we are now seeing a lot of populations resistant to Group I herbicides.  “Yields were being compromised and paddock hygiene was bad. Yields were probably being reduced by about 20% – 300-700 kilograms (per hectare).  “If paddocks were really bad, growers looked at fallow or pasture and sheep, but that was only managing it – it wasn’t going to fix it.’’

However, with the availability in recent years of the Groups H and C herbicide Velocity^®, from Bayer, farmers have been using it to target their bad radish paddocks.  “Growers were hungry for a new chemical and there was strong uptake, but only for use over small hectares. There was exponential growth and now it is consistently used,’’ Graham said.  “Farmers are using Velocity to manage their bad radish and they are getting better management of paddocks. They order it for about 20% of their program each year and use it around the farm.’’

Velocity is based on the novel active ingredient, pyrasulfotole, and also includes bromoxynil and Bayer’s crop safener, mefenpyr-diethyl. The pyrasulfotole interrupts several biological processes crucial to weed growth, while the bromoxynil, which acts primarily as a contact foliar herbicide with virtually no soil residual activity, further disrupts the photosynthetic process, resulting in a unique action against weeds.

“Previously, growers were going toward using two sprays, like Jaguar and then 2,4-D Ester,’’ Graham said.  “Now, if they have real nasty paddocks, they will hit them with Velocity early.  “It’s certainly making things manageable. By ideally targeting small weeds twice, we don't see any escapes.  “It’s a salvage operation in the first year and the return on investment is over a 20-year period. That’s what it’s about – planning.’’

With massive seedbanks, he said one spray in one year did not solve the problem and growers were also employing other strategies.  “In bad paddocks, farmers might go to a Roundup Ready^® canola to tidy it up and then come back to Velocity (the following year).’’  “They also may still fallow it – that’s still done a little bit.  “Burning windrows and chaff carts are also coming into play for weed seed management. There are now a handful of chaff carts in the area.

“Growers may also change to a later-sown wheat variety and get a couple of (herbicide) knocks, or also look to using a Clearfield^® system crop.  “If they can get a good level of control in a paddock over a number of years, they may be able to go back to Jaguar with a phenoxy product follow-up,’’ Graham said. 

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