A word to the wise on weeds

Claire TyrrellCountryman

Growers are urged to pay attention to detail when it comes to weed control.

This was the message at a wild radish master class held in Mingenew recently.

About 20 farmers attended the workshop, hosted by the Mingenew Irwin Group.

Keynote speaker Bill Campbell, from Nufarm, advised growers about different types of resistance in wild radish.

Mr Campbell urged growers to check for resistant radish via thorough seed checks.

“If you are getting problem radish, collect a cup full of seed from the survivors, ” he said.

“This way, you can test for different modes of action.”

He said there was a direct link between crop genetics and herbicide resistance.

In his presentation, Mr Campbell focused on the subtleties of radish resistance, referring to ‘stacked’ and ‘unstacked’ plant populations.

“Stacked resistance is a form of multiple resistance where plants in a population independently develop resistance to herbicides with different modes of action, and then through co-existence eventually interbreed to produce individual plants resistant to more than one herbicide groups, ” he said.

“Unstacked resistance is when a plant population as a whole has multiple resistances.”

Mr Campbell spoke about resistant radish population trials held in Nabawa.

Farmanco gathered data from the trial, which looked at resistance to phenoxy herbicides designed to selectivity kill broadleaf weeds.

The trial identified stacked and unstacked populations of phenoxy resistant radish.

Mr Campbell said he found radish resistance strengthened through incidental cross-pollination.

He likened the different types of resistance to a “jar full of jelly beans”.

“When you are looking at herbicides, you are dealing with different crop genetics, ” he said.

He stressed the importance of phenoxy herbicides when it came to controlling weeds.

“It is important phenoxy chemistry is the base building block for everything you do, ” he said.

“If you lose that phenoxy component, you can run into a brick wall very quickly. This is something we didn’t understand until recently.”

The trial looked at group B and group F phenoxy herbicides commonly used by farmers in the northern Wheatbelt.

Farmers were advised to consult their agronomist to determine the most effective mix of herbicides to control weeds.

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