Controlling mature fleabane is tricky. With funding from the Hugh Williamson Foundation and the Australian Government's Future Drought Fund. BCG research agronomist Angus Butterfield completed a research project on controlling mature fleabane, which is up next. The information shared is based on research conducted for the purpose of exploring fleabane control options, and should not be considered direct advice. Please note some herbicide rates and applications discussed may not align
with registered label requirements or maximum residue limits. We strongly encourage you to consult your agronomist or local adviser before implementing any of the strategies covered here. They can provide guidance tailored to your conditions, ensure compliance with current label requirements, and help you adhere to MRL guidelines. This podcast is sponsored by Action Steel. Today, I'm speaking with BCG research agronomist Angus Butterfield about his research into summer fleabane control,
specifically when it's mature. So not when it's at the rosette stage, but when it's elongated and it's mature because that's when people often have the trouble. So welcome, Angus. Thanks, Janine. Just for a start, can you give a little bit of a background on you and then why you are so interested in researching fleabane?
I'm originally from the outskirts of Melbourne, just out of a town called Hurstbridge. Third year at the Birch Cropping Group as a research agronomist. And the reason that I'm interested in this stuff is because it has been such a big issue for a lot of our growers. There's been growers contacting us asking what is the solution for this sort of issue, especially with a few of our wet summers we've had recently. It's become an issue as it's so hard to kill with some of our knockdown herbicides.
And where are most of those growers from? Angus.
So most of those growers at the minute are in the mallee sort of region. So anywhere from all the way up past sort of Balranald, all the way down to Birchip, but we are seeing it start to spread more and more into the Wimmera as well as the North Central.
And why are we seeing that?
It's been around for a little while, more of a Queensland New South Wales weed, Wade. But a lot of guys I've been talking to have said after the floods we had about ten years ago, it's come in. And just due to how many wet summers we've had recently, it's become more and more of an issue. Obviously, if we're going to dry summer, we're not going to see those weeds germinate over that time. So do you.
Think that the flood water helped disperse the seeds.
As it wasn't really around at the time? That's just what I've heard. But yes, I would have thought so. It's a windblown and I guess it can be spread by water as well. One of the biggest issues that they can spread from roadsides and fence lines.
Okay. So can you tell me a little bit about fleabane and why it is so hard to control?
Yeah. So it's it's a broadleaf weed. So it emerges sort of in that 10 to 30 degrees conditions. So we often see it emerge in springtime once it gets a bit of size about it. Its plant structure and phenology makes it really difficult to kill. It's quite tolerant to glyphosate, so your standard glyphosate spray won't really get into it. And the reason that is because it's got a low stomata count. It's got quite a waxy plant tissue.
It's got hairy leaves and they're quite small. So it's got all these sort of characteristics that sort of make it hard for our herbicides to translocate into. So it's a surface germinating weed so often. Once upon a time in our till systems, we could control it just because once it gets buried, it's quite hard to germinate. Germinates in our 1 to 2cm in depth. And also something makes it so hard is that you might only see 1 or 2 weeds in your paddock because it produces
about 100,000 weed seeds per plant. You can see that is a fair few and one where it can. Obviously, it can turn into a blowout in a number of years like quickly.
So why do you think it's important to research fleabane control at this stage when it's mature?
So we often see fleabane germinate in the springtime. So that's often under a crop. So it's quite easy to kill at those smaller growth stages. But we often don't get the chance to target them over those stages. So like for our lentils, the only sort of options we've got is until the end of harvest, which is desiccating. And if they've been sitting in the ground for two months, they've put a bit of a taproot in and they'll elongate pretty much as soon as it warms up so
often hard to target them at those stages. Also, there's some residual control that you can do. But again, just due to our love of lentils at the minute and our pulses, it's really hard to use any of those residual herbicides just due to plant back issues that we see with them now.
Can you tell me about your research project?
Yeah. So we're looking at during summer because obviously it does emerge quite early and we have actually seen it. I've seen two months ago at emerging in some crops. And if you've got something like lentils in or any sort of pulses apart from maybe chickpeas, there's no residual control. You can't spray it on top of it. You've sort of got to wait until you're desiccation stage. Same with
your wheat. There's like there is some options, but then you're in terms of residual control, but then you're restricted to your rotation. And there's not much flexibility there.
Right. So your research project is about fleabane control in that summer wheat period after harvest but before you put your next crop in.
Yes. Over that summer fallow period.
Okay. So what did you find?
So our research was a number of trials, but looking at that elongated fleabane. So when they mature a bit more natural tolerance to glyphosate and difficult to kill. We looked at a few different trials. First we looked at our first pass in the double knock situation. So we looked at a bunch of Group four herbicides mixed with
glyphosate with a standard paraquat terrador double knock. And then we looked at another trial with pretty standard sort of first passes with a range of different double knock options, usually a mixer with paraquat. Okay.
So generally speaking, most people would control this. Not in one pass. They would do the double knock.
As far as I can see, I don't think there's any sort of chemistry that we can use that will get it done in one go. Out of all the research I've seen and we've done, just a single pass is just not effective. Okay.
So what did you find?
Um, so we found a few interesting things. We found that a lot of our group four herbicides that are commonly used in the summer. Fallow didn't actually give us much more control than glyphosate, so starring dicamba and 240 ester, we naturally see. And these are all rates that are that were recommended by agronomists. We didn't actually see any differences between using those chemistries with glyphosate and using glyphosate alone. So what are the symptoms we saw were the burn
off symptoms from our paraquat. So it's suggesting that we maybe those chemistries aren't quite getting into the plant. And then we saw also two at 240 amine was better than our ester. So we looked at about 85% control. So it did improve control. But we're like like I said before 85%. You're getting 15% through. So we saw the symptoms from those treatments were more of the contact herbicides that we'd put on the seven days after. So we're saying that paraquat and our territorial spray in these
trials were doing most of the work. Those treatments were pretty much similar to glyphosate. Still getting a fair big seed set there for the next season, but the standout in this trial was really another product. I mixed with glyphosate, which was drop zone.
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So it's a 240 amine product so similar to a amine. But it has some some sort of surfactant package that makes it translocated into the plant better, which we saw. So it actually was 98% control. I think from seeing those results, it might suggest that our biggest issue is actually getting the herbicide into the plant. So the translocation. So all of these herbicides like 24D amine can kill it. It's just getting it in which is what we've seen. Wow.
So that's a group for again.
Yeah. Yeah. So all these chemistries in our first pass trial were all Group four chemistries. Okay.
So that was the first pass. So you found that the first pass the best was glyphosate with drop zone. That was the best. And then the second best was.
So our sort of two 4D amines as well. So out of our three different two 4D products you've got drop zone with their best control. And then we've got amine at our middle sort of and then our ester at the end, which was surprising because especially because ester has that bit of kick that most people. And yeah, it is a pretty standard sort of product that a lot of people would use.
So you said that trial that you were talking about, Angus, that was with the first pass being those specific differences. And then what was the second pass?
The second pass for all those treatments I just talked about was, um, two liters of paraquat and 20g of terrador.
Okay, so onto the second trial. Angus, can you talk to me about that?
Yep. So the second trial that we did looked at again in a double knock situation, instead of looking at the first spray that we do in that we looked at the second spray. So the one that's done ten days after the initial spray. So our first pass sprays were pretty standard at a glyphosate with a common mixer. But we looked at a range of different mixes, usually with paraquat in this trial.
What were some of those mixes?
So there was from this trial, there was a few interesting things from the second pass trial. So we looked at a range of different group 14 herbicides. So Terrador Rackstraw as well. We also looked at some camera sprayer rates. So we bumped up rates to four liters as well. So some of our better ones that we saw in the second pass trial were some of the camera sprayer rates. So higher rates of paraquat we fight with the higher rates that you're able to put through a camera sprayer.
We got better control. So we saw that our best control was with a very expensive brew. It had four rows of paraquat, foreign mils of amatol and 40g of toradol, which is very high, but we only saw 93% control. So we're looking at a quite an expensive spray versus what we what we talked about before with the drop zone is that it's probably about half the cost. Another interesting thing, we had a bit of a curveball treatment in here, and it was aiming for 52l, as well
as star rain at 500 mils just with a paraquat. Terrible. And we got 90% control. And that actually was the second best performer. So we're saying that there is a lot of different options and they can get quite expensive in the second pass. But by what I've seen, your first pass is the most critical stage. So you sort of want to put your money in your first pass
and just run the standard second pass. So we're seeing that glyphosate is not really working at all with our fleabane, because there's two group fours mixed together with just a standard double knock. We're getting very good control. We also saw that Pteridophytes are like it's a massive thing now in our summer spraying. It's a great bit of chemistry, but in terms of fleabane, we didn't see any differences between using that and with and without with paraquat either.
So the drop zone in the first pass was how effective?
98%.
And then in the second pass trial, what was the most effective?
93%.
But that was with the really expensive brew.
Yeah. And that was through a camera spray as well.
So do you have any data, Angus, on how much fleabane takes out of the soil?
I haven't got any data on it necessarily, but yes, it's got a taproot. So evaporation will happen in your top 20 to 30cm, so you'll lose it anyway. But your stored water is underneath that. And it does have a taproot and can tap into that. So that's with
any of our summer weed stuff. And because it's so hot, it matures so quickly and can suck that water out quickly, you can just see even this year, different sort of summer spraying approaches, um, can make the difference between having a crop and not having a crop in a year like this, just because it's been a heavy reliance on that subsoil moisture.
So what would your advice be, Angus to farmers that are dealing with. Or they're seeing fleabane popping up now in their paddocks.
Oh, the first thing you'd have to do would be monitor it as close as you can, make sure you know it's there. So if you've got any opportunities to control it when it's small, do that. That's your best bet is controlling it when it's at that immature stage like most don't get the opportunity to do that and you have to come back, come up with a strategy. If there's any sort of options, you can do lentils. If you've got some issues in that desiccating would be
definitely the way to go. And even a double knock desiccation in cereals. Depending on what your rotation is like, there is a bit of residual control options, but it's probably a bit late in the season now. Um, but yeah, just monitor it and get on as quick as you can because as soon as they start getting a bit in size, they are very hard to kill. Even with those herbicides that I talked about, you still want to get them early and can be saving some dollars there
as well. You've just got to stay on top of it because as I said before, it's a windblown weed. So regardless if you control your paddocks, if it's on a fence line or if it's in a neighbour's paddock or it's on a roadside, it can still blow over into your paddock as well. So it's just constantly being on top, like a lot of our summer words. Just making sure you can just stop that set, that seed
set as much as you can. Like any way, depleting the seed bank is your most important thing because all of these can stay around your soil for years, and the chemistry you use in the first pass seem to be more important in controlling it, rather than trying to make up for it in the second pass. So spend your money in your first pass rather than your second pass. Based off the research we did over the summer, that would be my recommendation.
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