Sheep blowfly eradication on Kangaroo Island

South Australian wool producers are battling the challenges of fly strike, a fatal condition causing significant sheep deaths across the state.

The vast majority of fly strike deaths are caused by the Australian sheep blowfly, which is creating economic challenges for primary producers as well as an ongoing animal welfare challenge.

Lockie Bell is a fifth generation farmer on Kangaroo Island and says he is finding it difficult to combat the issue.

Fly strike can be pretty horrific.

I went around a mobber sheep on a Friday night just making sure that there was none struck and that there was no issues.

Went back on the Monday and there was 3 already dead in the corner of the paddock from a from a from fly strike and there was another three struck.

That just proved to me how how quick things and you think you're OK to being in trouble.

Fly strike is a really significant issue.

Nationwide it costs about $365 million every year and here in South Australia it costs about $60 million every year.

In terms of economic losses, fly strike is definitely something we have to put in a management calendar.

If you like, we crutch twice a year so that there's less chance of a breach.

Fly strike, just depending on seasonal conditions.

Obviously if you get thunderstorm activity through the summer, hot steamy conditions, that's pretty ripe for for fly strike.

We'd probably be just about situated in the worst area on the island for fly strike.

We're just down in a bit of a valley where the wind doesn't sometimes come, so the the flies are able to move about pretty freely.

So look, obviously the biggest cost with fly strike is the deaths and the loss of wool.

Every fly strike you're going to lose a portion of your of your fleece unless you catch it very early.

Only a small percentage of the sheep is impacted.

They seem to survive but if they're, you know, got big patches, a lot of them don't survive.

Through generous investment from industry and government, leading scientists at the South Australian Research and Development Institute are working side by side to tackle blowfly strike in a world first targeted and live research pilot programme located on Kangaroo Island.

SIT is stands for Sterile Insect Technique, and in its simplest form, what it means is that we flood a natural area with sterile males of that insect species.

And by doing that, it means that the fertile females will generally only mate once.

And this species is one of those ones where they only mate once.

And so the chances are that when the females mate with a family, they're more likely to end up mating with a sterile male in the wild.

And so that means that that female fly can't lay any eggs.

And so that means she can't 'cause fly strike and she also can't start the next generation developing either.

Chances are that she'll end up with a dumb fella and that's the end of the line for for her.

The fact that we've got multiple partners in delivering this project means that everybody has a different understanding of the situation.

Everybody has a different contribution to eliminating sheep Bloke fly strike in Kangaroo Island and I'm talking about Meat and Livestock Australia, Australian Wall Innovation, Animal Health Australia, the South Australian Sheep Industry Fund and the University of Adelaide.

And that's what makes collaborations really important because everybody genuinely brings something different that's going to make a difference.

So it's a big problem around the world, New Zealand, United Kingdom, South Africa, so a number of sheet producing places.

It's really significant and it means that things like mulesing need to occur or chemical applications.

So if we can reduce or eliminate those through this sterile insect technology, that will be incredibly exciting as well as great economically and great for animal welfare.

It's chemical free and it has a considerable animal welfare ramifications and the fact that we're doing it on Kangaroo Island, which is a real localised area, so we can really get an understanding of how to measure the impact, creates another value proposition for us.

So over time we'll be able to see well if this works well and we're expecting it to, then we can roll it out more broadly throughout SA and the world.

The demountable facility was specially designed and purpose built to rear sterile insects which if proven successful, could be deployed to other areas of the state.

Helen Brody from the South Australian Research and Development Institute helped set up the facility and now manages it with a small team based on Kangaroo Island.

It doesn't matter what insect you mass rear, they generally breakdown into the same kind of steps.

So you always have to have a breeding colony that produces the eggs.

The next step is to actually harvest those eggs and transfer them onto an appropriate larval diet, so something that the maggots can get into.

They can grow nice and fat and quickly in it and that's always done in another room.

Often each life stage has its different preferred climate conditions.

Once the larvae are finished growing, they generally leave the diet and they drop down into something like a sawdust.

In our case, we use vermiculite and that gives them somewhere nice to Burrow down and turn into the cocoons.

So at that point we then harvest them, we mature them to the right stage.

We actually coat them with a dye first so that later down the track we can detect them in the wild when we catch them in traps.

And then the very last stage before we actually release them is to actually sterilise them.

And we do that in a machine.

It's specially designed for sterilising insects and it delivers a dose of X-ray radiation and it's just the right dose that it only effects their reproductive organs and nothing else.

So we hope to in a few years time, be at the point where this facility is generating 50 million flies every week.

It's really good to have the scientists on board.

Obviously they're they're experts in in enabling the whole thing.

Obviously, it's not going to solve 100% of the fly strike.

We've still got other flies that give us a strike, but this one is so vicious that we can maybe soften our management, not be so rigid and just the animal welfare part of it too.

Look, I hate seeing a sheep absolutely blitzed by flies.

Obviously, if we can eliminate 80 90% of our fly strikes, that'd be a terrific result.