The last knock

5 November 2023 by
Seed Terminator, Kelly Ingram

"Yeah, nah bro!"

“Yeah, I’ve crop topped my crop with glyphosate, so nah I don’t need to use harvest weed seed control.”

This was a grower who understood the need to do something about weed seeds, but didn’t understand the benefits of a double knock.

Just about everything in weed control these days is about double knocks to both prevent herbicide resistance, and to enable us to manage weeds that are already resistant.

There are chemical / chemical double knocks e.g. glyphosate followed by paraquat.

Chemical / cultural double knocks e.g. pre-emergent herbicides in combination with competitive crops.

And the best double knocks of all are chemical / mechanical double knocks. E.g. crop topping ryegrass followed by a Seed Terminator.

A Seed Terminator is a good idea for every crop, and it’s an especially good idea for crops that have been crop topped, because if glyphosate is the last herbicide they see this year, that is a massive selection event.

We have limited herbicide options to stop the seed set of those weeds that are staring you in the face right now, so glyphosate gets a hammering. It’s a pretty big spring and a big crop for most of the country this year, which means the weeds are going to yield a lot of seed as well as the crop.  

If you’re growing feed barley or canola there’s a good chance that you sometimes crop top with glyphosate prior to harvest for ryegrass seed set control, and this year is shaping up to be a big crop topping year.

I get it. If you have flowering ryegrass in a barley or canola crop, you should definitely pull the trigger, and do what you can to stop seed set, despite the risk of resistance. Glyphosate could reduce seed set by 95% when applied to flowering ryegrass.

It’s a bit like if you’re dying of thirst in the desert, and all you have is a carton of beer, you should definitely drink the beer, despite the risk of it dehydrating you in time (plus if you don’t make it, at least your last hours were enjoyable!).

Perhaps the fastest track to glyphosate resistance is using glyphosate alone for ryegrass control on fencelines. And I would argue that the second fastest is using glyphosate to crop top ryegrass in spring.  I say this because this is the last herbicide that crop will see. There’s no ‘second knock’ herbicide coming along behind it to control the survivors. That’s where the terminator comes in.

We know that if a weed is resistant to a herbicide, it’s also resistant at the seed set control timing, but it’s not resistant to cold hard steel spinning at 3000rpm.

How important is glyphosate to your business? Most growers would say it’s important enough to look after.

The Seed Terminator should be the last thing your weeds see each year.

Yeah, yeah bro!

The Terminator Agronomist
Proudly brought to you by Seed Terminator 

Please note this advice is general in nature and not based on your specific circumstances.

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