Varroa mite, fall armyworm, cauliflower breeding

Vegalogue is a podcast from Australian vegetable peak industry body AUSVEG. Each month we take a look at issues affecting the Australian vegetable, potato and onion sectors, unpacking levy-funded research and meeting some of the incredible people who make up the vegetable industry.

This month, we discuss:

• How the transition from varroa mite eradication to management has gone, and the priorities for the new plan.
• The cross-agriculture collaboration to manage Fall armyworm amidst the largest outbreak of the pest since it was detected in Australia.
• Why cauliflowers need a sun hat, and what growers are looking for in new cauli varieties.

Guests:

• Zarmeen Hassan, National Manager of Biosecurity and Extension, AUSVEG
• Dr Melina Miles, Principal Entomologist, Queensland Department of Agriculture and Fisheries.
• Eliza Seymour, Regional Business Manager - Victoria & Tasmania, Bayer Vegetable Seeds.

Thanks for listening to Vegalogue! You can find out more about AUSVEG and the Australian vegetable industry at ausveg.com.au. Subscribe to our newsletter, or follow us on Facebook, LinkedIn, Instagram, Tik Tok, or Twitter/X.

Chapters

• 1:26 Varroa mite - transition from eradication to management
• 12:08 Cross-ag collaboration on Fall armyworm
• 18:47 Cauliflower breeding with Eliza Seymour

Transcript

Because at the end of the day, you're out in an open system where there's water, there's wind, there's rain, there's hail, there's bugs.

So the more leaf wrap that you can get on a cauliflower head, the better, but it also needs to not muffle it.

So it's a Goldilocks effect.

Welcome back to the Vegalogue podcast, a dialogue about the Australian vegetable industry from Ausveg.

I'm Tom Bicknell.

We're going to be talking unpleasant bugs this episode, kicking off with an update on varroa mite and the transition from eradication to management of the bee parasite with Ausveg's Zarmeen Hassan.

We're also going to hear from Dr.

Melina Miles from the Queensland Department of Agriculture and Fisheries about the latest efforts to advance and share practices to manage fall armyworm.

A caterpillar that's causing serious headaches for growers of sweet corn and an alarming number of other crops.

But then happily moving away from bugs, we're going to take a walk through a cauliflower field to understand what growers are looking for in new varieties with Eliza Seymour of Bayer Vegetable Seeds.

So let's go now to Zarmeen Hassan, Ausveg's National Manager of Biosecurity and Extension, to hear how the effort to manage varroa mite is going.

Thanks again for joining me, Zarmeen.

So one of the biggest stories in biosecurity in the past couple of years in Australia has been the entry of varroa mite.

We were one of the last countries to get this little bee parasite, and the response to it has, I believe, been the largest in Australian history.

So there's been this huge effort to eradicate it, but ultimately in September last year, the decision was made that that wasn't feasible anymore, and the plan had moved to management.

In the seven months since then, how's the transition to management gone?

Thanks for having me, Tom.

Yes, absolutely, it has been one of the largest responses out of the emergency plant pest response deed, a $100 million response.

And to your point, we are the last country in the world that was free of varroa mite.

We are no longer free of varroa mite.

And based on that, it was important that we give it a red hot shot to try and eradicate.

So industry with government put a plan behind the eradication.

A number of activities and a number of locations where it had spread, we realized that it is no longer eradicable.

And so with government and industry through the emergency plant pest response deed decided to transition to management.

Now that transition to management was decided back in September, 2023.

And it's not a switch on and a switch off.

So the whole process of agreeing to what exactly a transition to management entails is a process of negotiation and agreement.

And that took about four to five months.

And so a lot of the last seven months that you are talking about has been focused on agreeing what the costs need to be, what the key activities are required as a transition to management.

And in essence, a transition to management is moving the pest from an eradication response to enabling industry to manage it.

Now here, industry are two industries.

So it's the beekeeping industry, which involves a whole lot of commercial as well as hobby beekeepers.

And then it's the pollination dependent industry.

So industries like ours, berries, almonds, vegetables, et cetera.

And so the transition to management has essentially focused on four key activities.

One is completing the eradication response and ensuring that all of the compliance that was required out of beekeepers as an industry is completed, that there is an orderly stand down of the response, including all of the organizational structures that were set up to the combat jurisdictions.

And so there's an orderly stand down and you don't just disappear because we've been very visible with the beekeepers and the growers in the New South Wales.

So that has been the key focus initially of the response plan.

This transition to management is a 24 month plan, which is unconventional.

Normally the transition to management plan is for 12 months, unless there are exceptional circumstances.

And the exceptional circumstances here is that for the first time, the beekeeping industry needs to look at pest and disease management in their beehives.

As an industry, they've never had to do this.

For our industry, the vegetable, potato and onion industry, or any of the other pollination reliant industries, pest and disease management, IPM, crop monitoring, et cetera, is second nature to us.

This is what we do, what growers do, to grow a viable or marketable crop.

For the bee industry, they've never had to do it.

So with the incursion of varroa mite, it essentially is changing the way the industry will operate.

And so a significant component of the transition to management plan is educating the beekeepers on how to manage the hives in view of the varroa mite incursion.

In fact, about 70% of the budget is actually going behind extension activities across all states.

So not just New South Wales, where the incursion happened, but each of the jurisdictions or each of the states will have varroa development officers that will enable beekeepers and work with beekeepers to manage their hives, to ensure that they're doing proper crop monitoring or bee hive monitoring, that they're doing alcohol washes, that they're looking after their bee hives like we would look after their crops.

Again, that's not something they've done before, so it really is changing the way they do business and so stewarding them through that process.

So that is a significant component of building industry resilience.

So that's what the large part of the transition to management plan is.

And then through building the resilience of the beekeeping industry, the transition to management plan also is looking at slowing the spread of aroa.

And that means that bringing in hives that are clean on farms and supporting farmers to send out clean hives.

So there will be a bit of a learning process there as well to look at hives that come in to ensure that they come in clean and that they leave clean.

So that's part of building resilience as well and slowing the spread of aroa mite.

So that's an immediate response.

But then also what we're looking at as part of the transition to management is what does the industry need for the future?

And while that doesn't, research doesn't necessarily come under the purview of this transition to management plan, understanding what the future needs are will be part of the plan.

And industry is already responding to aroa mite and through the threat.

So, for example, the vegetable industry has invested in looking at alternate pollinators to understand what are the other pollinators that do exist within, let's say, the cucurbits crop, which has been impacted in New South Wales, and what are the most effective ones, and then, you know, on a long term potentially looking at if they can be mass-fed.

So, for the cucurbits crop, and the reason I'm talking about cucurbits is because in the vegetable industry, cucurbits are reliant on managed pollination, and they were also the crop that was impacted in New South Wales' response to the incursion or the response plan.

So, there we're looking at, again, understanding what are the pollinators that are present, because there were no bees present, because all the bees were euthanized.

So, what are the pollinators present, and which are the most efficace ones?

And so, the two that we're looking at right now is hover flies and drone flies, and understanding how effective they are on pollination.

So, there is a future outlook as well to look at what work needs to be done, to ensure that as industries that are reliant on pollination that our crops are safeguarded.

How's the vegetable industry been contributing to the varroa mite response, and how has that cost been managed?

So, the response plan as well as the transition to management plan is cost shared, which means that each of the parties to that response have a certain component of the cost that they will pick up.

So, the total cost is $100 million.

The vegetable industry's component is up to $800,000 for our cost shared part of the response plan.

Now, the way the vegetable industry is funding that is that over the few years since Tomorrow Potato Salad arrived in 2018, we have had an active emergency plant pest response levy, so EPPR levy, both for vegetables as well as potatoes.

Now, it's important to note that varroa mite does not impact potatoes, so potatoes are not part of the response.

But over the years, we have collected and built a reserve that's managed out of Plant Health Australia, and that reserve is sufficient for us to pay back our cost sharing for the varroa mite response, which I think puts us in an advantageous position, so we don't need to go out and increase any levies so that we pay back our cost of the response.

A lot of industries may need to raise an emergency plant pest response levy, and the way that transpires is that the Commonwealth underwrites the share of the industry's cost, and then over five, ten years, depending on how industry must recover that cost, they pay back the Commonwealth.

We did that during the tomato potato cellular response, TPP, and we incurred a debt to the Commonwealth.

This time, we are not incurring that debt, and that means that we are able to pay back a cost as and when it incurs.

And so we've proposed to the industry that we continue to have active EPPR levy, so that any response that comes up or any incursion that comes up, that we are able to respond instead of having to go to industry and raising funds for that response.

It's more efficient, it's more effective, and the money is managed by Plant Health Australia.

It builds a reserve there.

Audited, transparent, so it's accessible through any auditing process.

So, yeah, so that's out for consultation now.

If there's any grower that wants to come and give feedback, we have contact details there as well.

Fantastic.

Thanks for the updates, Zarmeen.

Thanks, Tom.

You have a good day.

Bye.

You're listening to the Vegalogue podcast, brought to you by Ausveg.

Growers across the country have been struggling to deal with the resurgence of fall armyworm this year, with numbers of the exotic pest bouncing to their highest levels since it was first detected in Australia in 2020.

Initially a problem in northern growing regions, fall armyworm has now been detected in all states and territories except South Australia.

Equally concerning is its appearance in a range of additional crops, well beyond the sweet corn, maize and sorghum that had previously borne the brunt of fall armyworm damage.

Helping growers to handle the new pest is the focus of a levy funded project being run by the Queensland Department of Agriculture and Fisheries, called the National Fall Armyworm Innovation System for the Australian Vegetable Industry.

At a recent field day run by VegNet, New South Wales and Local Land Services, I had a chat with Dr.

Melina Miles, the principal entomologist with the Queensland Department of Agriculture and Fisheries, about current fall armyworm management practices and what the project's objectives are.

Melina, we're here today at a field day in Richmond on the outskirts of Sydney, and you're presenting to growers some of the latest fall armyworm research.

For those who might not be aware, could you tell us a little bit about fall armyworm and its entry into Australia?

So fall armyworm arrived in Australia in 2020, was first detected in far north Queensland, and then very quickly by, and that was about January, and by September, it had made an appearance across most of eastern Australia.

So it's a moth, which produces a caterpillar.

For the first time, I guess, in terms of both broadacre and horticultural crops, particularly sweet corn, we've got a pest that is a severe defoliator in the vegetative stage, not something that we've ever had to deal with before.

And I guess, you know, it's now in every major growing area.

We've had 2020 was quite a severe infestation in the north.

And then we've had two years that have been relatively quiet.

And this year, sort of particularly from the beginning of 2024, we've seen, you know, pressure numbers, densities, damage that we haven't seen in previous years.

So it's been quite a wake up this year.

And when it comes to managing fall armyworm, does best practice look the same across Australia or does it vary by region and by crop?

Oh, it varies very much by crop.

I guess the, you know, the sort of quality requirements and the response of sweet corn to fall armyworm is much more severe than, say, in maize and sorghum.

So, you know, I think we can immediately separate out those two industries in terms of the way they are managed.

I think from a Broadacre point of view, you know, we've really managed fall armyworm very well in the past two years with minimum chemical intervention and a move to early planting, so planting in spring rather than planting in summer, has meant that the majority of crops have avoided higher fall armyworm pressure.

This year, the pressure has been so high, and we've also had a lot of late cropping, that a lot of crops have fallen into that and met really high fall armyworm pressure.

And there's been a lot more spraying as a consequence.

In horticulture, in sweet corn, you know, the strategy really is to spray that pest to minimise the impact on the crop.

And that's, I guess, you know, unfortunately the management practice at the moment.

And could you give us an overview of the project you're working on and what that's trying to achieve?

Yeah, so this fall armyworm area-wide management project brings together the industries because we're the recognition that fall armyworm doesn't recognise industry boundaries.

We've done this before with hilly coverpa, with cotton and grains, which was done very successfully in the early 2000s.

And we're sort of hopeful that we'll get a similar kind of outcome for the industries with fall armyworm.

And it really does focus on learning, on an appreciation of the biology, the ecology, the interaction with natural enemies, the sort of common threads across the landscape, regardless of whether you're growing sweet corn or maize, whether you're feeding it to people or whether you're feeding it to animals.

So, you know, real emphasis on bringing people together to develop that common understanding and I guess bringing the R&D in along with that as well.

And as a big part of the project, engagement activities like we're doing here today at this field day?

Absolutely.

That really is the core business.

You know, at the moment, there's not a lot of R&D sort of operating alongside, so we're sort of drawing on what we know about other pests and how that might relate.

So the emphasis is on bringing people together to communicate, you know, the little research that is going on currently, but also to share the experiences and to sort of understand what it is that people are doing that they think is working, why it might be working.

You know, really, I guess the focus is on developing an understanding rather than just communicating, you know, technical information per se.

And so what's next for fall armyworm research?

Well, I think, you know, I guess given a season like this, there's a real emphasis on understanding how much damage is too much damage.

That's the approach that we're taking in grain sorghum and maize for grain.

So developing thresholds, it will help growers to make a rational economic decision around whether they can afford to spray, whether it's actually going to deliver them a return on that expenditure.

For sweet corn, there really is a need to, I think, I guess in my opinion, there are some fundamental changes that need to be made.

The crop is highly responsive to fall armyworm, so you can't allow too much damage.

It doesn't leave very much wiggle room in terms of minimizing insecticide use.

So there are some real challenges around how do we change the system to reduce the very high reliance on insecticides that we currently have and take advantage of the natural enemies and the other biological control that we know is there, but currently can't get a foothold given the high intensity insecticide use.

This project is funded by Hoard Innovation using the Vegetable Industry Research and Development Levy and contributions from the Australian Government under project code VG22006.

Did you know that slip-slop-slap even extends to cauliflowers?

Just like us, if cauliflowers get too much sun, their head can get sunburned.

We turn red, they turn a creamy yellow.

Traditionally, many growers would snap a leaf and fold over the cauliflowers head, also known as the curd, to keep it shaded.

Your varieties usually have enough leaf cover to protect them, however, saving a lot of labor and keeping cauliflower heads clean and white.

Ausveg's Deborah Hill had a chat with Eliza Seymour of Seminus, part of Bayer Vegetable Seeds, about what breeders and growers are looking for in a new collie variety.

Today with Ausveg, we're down at Werribee South to have a chat with Eliza Seymour from Seminus, the vegetable arm of Bayer, to talk about collie flowers and the seed development and variety development of collie flowers, particularly today.

So welcome, Eliza.

I'm so pleased to have you as part of this program on the Brassica feature.

What's happening in the collie flower world?

At the moment, so us specifically in the vegetable team in Bayer, so I work under Bayer Australia and there's Seminus and there's DeRoyter, so the two brands, but in our Seminus open field collies at the moment, we've got a few different genetics that we're just trialling out in the summer to autumn time slot.

So in Werribee South here, we're just at a growers' farm and they run cauliflowers and most brassicas 12 months a year and those 12 months are broken down into specific seasons and then you've got specific genetics for different seasons.

So these ones are really testing for their suitability for harvest at this point because some have clearly been harvested already.

Yeah, no, they came through on Friday and it's always a really good look when you sort of come through after harvest, you know, I've been checking this throughout the season.

They've taken about 12 or 13 weeks before this stage, but you sort of go, right, where's the commercial crop at?

You know, they've harvested once and they've got maybe 20 or 30% of the crop, whereas compared to our genetics, you know, how much of the crop have they got?

And ultimately what you want to find is a variety that's really consistent so the grower can know that they're going to go through once or twice rather than three, four, five times, because that's time and money.

And it's also, you know, when the market is really good, which is what the cauliflowers are at the moment, they're really good prices, you want to know that your crop is going to be ready and you can go through and wipe it out at once.

So when you're coming in now to, and I guess over the last couple of months, what sort of characteristics are you looking for in particular to say, yep, this one's going to be commercially viable compared to, let's scrap that one.

Yeah, yeah, so before these three varieties have even gotten to this stage where we've got sort of, you know, a few hundred plants in a row, we do a screening trial of about 20 or 30 of those varieties in this exact time slot, just to see whether they could take it to the next level.

And really what we're looking for is a nice strong frame, really nice head, you know, no disease issues.

What do you mean by frame?

What does that refer to?

Well, when we're having a look at a cauliflower, so you've got the leaves and then you've got a head.

And what you're harvesting is the head, you don't sell the leaves, but what you really need is a strong frame, like a strong body to get the cauliflower through whatever conditions it's going to deal with.

So the head is actually quite well buried, isn't it, within that leaf cover?

Yeah.

And that's what we're looking for.

We're looking for a really nice head that's ultimately going to, you know, match the specifications of what the growers need to then sell it on to a retailer or a supermarket, but you really need a nice frame.

And it's funny because you don't, yeah, at the end of the day, the consumer doesn't see the leaves, but they're such a vital part of a cauliflower and making sure that it does sort of develop all the florets that it needs to, develops the growth and the size in whatever conditions it is exposed to.

So my understanding is that obviously you need the leaves for photosynthesis and growth and all those sort of things, but cauliflowers tend to get sunburn as well.

Yes, yes.

So I think it's gotten to the stage where most varieties are pretty good.

If they're going through some adverse conditions, you might not get as much leaf growth, so you don't get that big, you know, frame to protect it from the sun.

So you can even see here, you know, that's providing an eyeshadow, that's providing an eyeshadow and ultimately the head wants to be protected.

So if you don't have that leaf mass, the cauliflower head is more likely to get exposed to the sun.

And in the current genetics, and what happens with cauliflowers naturally is that when they expose to the sun, they get a little bit yellow, but when you do have that protection, it stays nice and white.

So what we call this is the inner wrap, or like the inner jacket of the cauliflower.

These ones?

Yeah, yeah.

And growers really like to see a nice sort of inner jacket area just because they know that it's going to be nice and protected.

But there's also, it goes into, you know, this will get cut, you know, put in a crate transported, you know, there's dirt and things.

Because at the end of the day, you know, you're out in an open system where there's water, there's wind, there's rain, there's hail, there's bugs.

So the more leaf wrap that you can get on a cauliflower head, the better, but it also needs to not muffle it.

So it's a Goldilocks effect.

So you sort of need enough, yeah, enough that's protected.

So visually as a harvester, when would you say, right, this one's ready to go?

This one's probably, this one's absolutely ready to go.

They would have come through, they came through three days ago and this will probably get harvested in the next few days.

Something else we're looking at is just the ability to hold that head.

So yes, they did come through Friday.

This probably wasn't big enough.

Yeah.

And they might come.

Yeah.

It hasn't turned yet.

So they might come through in the next few days and you really want that collie head just to hold because it can tend to blow out sometimes depending on the weather conditions.

What do you mean by blow out?

Do the florets sort of start to?

Yeah, they start to separate.

It starts to look a bit ugly and lumpy.

And sometimes that is accepted in the market depending on the supply and demand and generally the specifications have a certain size they want and the look that they want.

And if it does blow out, it's just not worth the farmer sort of harvesting it and putting it through that system.

So how many varieties are in this plot that you're assessing?

I'm going to say, so there's our three trial varieties and usually the grower will run with one or two varieties for a certain season.

So like say over summer, they're getting to the end of their summer cauliflower crops.

There's probably only two or three varieties that you'd see on a large scale.

Some growers might be doing sort of a big semi-commercial trial.

So new genetics coming through, they're not quite pushing it to 100% of their crop.

They might do 20% or 50%.

But you'd usually see only really one variety in a big area like this and then they might move to another one because this will get them through a week or two of harvesting and then the next.

So when you're doing a trial plush, this is still a commercial crop for the grower.

So you're just assessing it as he's commercialing it?

Yeah, because ultimately you want to put it in their system.

You don't want it to be treated specially.

You just want to go right.

Is this going to suit your system and the way that you currently operate?

And if it does, fantastic.

I mean, when we're talking about crops other than cauliflower, it's totally different.

But with collies, you really just want to be able to set it in there.

If it works really well, that's excellent.

And if it's going to provide that added benefit, it's faster, it's a nice, brilliant white head, there's all these things that we look at.

So at the moment, that's sort of what we're assessing.

And ultimately, you want to give the grower confidence to move it to the next level.

Hello.

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Vegalogue is produced by Ausveg, the peak industry body for Australian vegetable growers.

You can find more news and information from Ausveg at ausveg.com.au on our social media channels or in Australian Growr magazine.

Thanks for listening to Vegalogue, the podcast that explains a cucumber only becomes a pickle after a particularly jarring experience.