Is Paraquat on the Ropes?

24 June 2024 by
Seed Terminator, Kelly Ingram

Is Paraquat on the ropes?

Being on the ropes isn’t always bad. It worked for Muhammad Ali using the rope-a-dope technique against George Foreman in the ‘Rumble in the Jungle’ in 1974. Ali lay back on the ropes, keeping his head out of arms reach, while Foreman pounded his body. After 8 rounds of pounding, Foreman was exhausted, and Ali put him on the canvas.

If you haven’t seen the doco “When we were Kings”, make sure you check it out. Ali and Foreman travel to Africa for the rumble in the jungle. In the training in the lead up to the fight Foreman cuts his eye so they have to delay the fight for a couple of weeks. They fought in the middle of the night to line up with prime time TV in America, and it was the biggest TV audience in history (at the time) with an estimated 1 billion viewers.

But I digress….

Why would I say paraquat is on the ropes?

Well it isn’t, but there could be trouble ahead.

Issue number one is herbicide resistance. The resistance testing labs around the country have started to pick up a few paraquat resistant populations of ryegrass. What is even more concerning is that these populations are often also resistant to glyphosate.

Dr. Peter Boutsalis from Plant Science consulting says they have detected at least 20 glyphosate and paraquat resistant ryegrass populations in the southern states, and he has also confirmed paraquat resistance in fleabane.

Dr. Roberto Busi from UWA has found about six populations of ryegrass from Western Australia that is resistant to paraquat and glyphosate.

Most of these populations are from fencelines. Yes that’s right, we are destroying our best herbicides on the least productive part of the farm. We need a different approach here, and this is a topic for another day, but in short, it’s not a good idea to spray glyphosate alone on the fenceline.

You’ll kill that herbicide then, as some growers have already done, you’ll kill then next one on the shelf, paraquat. Then what?

Issue number two is that paraquat is up for review by the APVMA. It has already been banned in other countries due to its toxicity, and hopefully it doesn’t come to that in Australia, but there is some level of risk of this happening.

What do we do? Give in and say, “well they’ll probably ban it anyway so there’s no harm in abusing it now”.

Or do we assume that paraquat won’t be banned, and it’s worth looking after as things will get really hard and expensive when we have glyphosate and paraquat resistant weeds?

I think the latter.

How to look after paraquat

Below is a list of everything I can think of

1. Don’t use glyphosate alone on fencelines and firebreaks. You’ll develop glyphosate resistance and then you’re reach for the paraquat. If you’ve been doing this for a while, it’s time to stop. You may need to invest in a better firebreak sprayer with some added safety for the dude behind the wheel.

2. Don’t just use the old school double knock of glyphosate followed by paraquat. Yes, continue to double knock, but do it new school. Add mixing partners to both the glyphosate and the paraquat. Pre-ems and knockdown spikes.

3. If you’re doing paraquat followed by paraquat, it’s probably because you already have glyphosate resistant ryegrass. You’ll need mixing partners with each shot of paraquat, and you’ll need to be vigilant. If you see any survivors, eradicate them.

4. Give Spray.Seed a run now and then. Paraquat + Diquat. Yes, it’s the same herbicide group, but there has been a bit of variation in the test results showing that sometimes Spray.Seed works better than paraquat alone on the resistant populations.

5. Glufosinate (Basta, Liberty, Biffo etc.) is the other knockdown herbicide. Unfortunately, it isn’t much chop on most of our weeds in the Australian climate (winter spraying), but it may be useful at high rates through a camera sprayer. We may also work out a mixing partner to get this product to work one day so watch this space. Having said that, we don’t want to go there. Glufosinate is a long way behind our current knockdowns.

6. Spray small weeds. Fencelines and firebreaks are typically sprayed when the weeds are huge, and you’ve run out of other jobs to do. This needs to change. We probably need to start spraying fencelines before the weeds even emerge with residual products. There’s a growing range of products with long residuals that can go on the fenceline. Once again, you’ll need a firebreak sprayer with good safety built in for the operator.

7. Use something mechanical on the firebreak. Slashing, cultivation, hay cutting etc..

8. Continue to belt your ryegrass seedbank into oblivion in the paddock with everything you have. Chemical and non-chemical. If you have a really low population, double knock plus spikes and pre-ems will continue to work for years. If you have a high population, and glyphosate/paraquat resistant ryegrass moves from your fence to the paddock, you’ll have your work cut out for you.

9. Cultivation. We don’t really want to go back to working up and working back before we seed. If it comes to it, we may need some form of cultivation at seeding one day. This is the last resort, let’s try everything else first.

10. I can’t think of a tenth thing, but I got so close to 10 I felt like I needed to put it down. If paraquat is on the ropes, let’s make it a rope-a-dope experience for the weeds. It worked for Ali, it can work for paraquat too.

The Terminator Agronomist

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P.s. Ask the terminator a question by return email, and get a blunt answer next month.

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

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