A BLOOMIN’ NUISANCE

THE spread of a colourful, yet invasive, weed is becoming an increasing issue for local farmers, with the now ever-prominent gazania a threat to potential harvests.

Loxton broadacre farmer Paul Kaesler said he “could not be happier” with this year’s bumper crop, however, the recent wet season – which has potentially yielded the first positive harvest in several years – has also encouraged the prominence of the gazania weed.

“We had to eventually have a good year, given we’ve been through so many bad ones,” Mr Kaesler said.

“Now we’re just hoping the rain stays away for harvest so we can get most of it off before it gets damaged.

“… (However), the gazanias have remained a problem – wherever they grow, they remain tenacious and strong, affecting the soil and stopping the plants from growing.

“They just take over, and we find the root system and their fine, small seeds just spread, and spread and spread.

“They’re definitely our biggest problem weed, and in some cases, they can take 50 per cent of your yield away.”

Originally hailing from South Africa, the gazania was introduced to Australia during the 1950s and 1970s as an ornamental garden plant due to its bright colouring and hardy growth.

The pest is a particular threat to yield losses in grain production, as the weed’s root system takes all the moisture from the crop.

Alongside Victoria, New South Wales, Tasmania and Queensland, gazanias have now been declared as a weed in South Australia with only sterile varieties able to be sold within the state.

However, the gazanias prolific presence has unfortunately already been cemented in the region.

“It’s only been in the last 10 years I have really started to notice them,” Mr Kaesler said.

“They love the wet weather, and about five to six years ago, we had three or four wet summers in a row and that encouraged them to grow and transfer across (into the fields).

“While they never really used to like it in the dry land as much, but I think they have adapted and have just gotten worse and worse.

“(Additionally), we think they are being spread by the road graders, cars, and even kangaroos, cattle and sheep.

“(Current research) is saying that this weed will just completely take over if we don’t get on top of it.”

Mr Kaesler said though he had been previously trialing sprays as a method to kill the weed, it has not been as successful as he hoped.

“The chemical just doesn’t touch them, so we’ve gone back to try and ploughing them out,” he said.

“We believe the chemical is going to have to be some type of residual – so, it will go into the soil to stop the roots from growing as well knock them over at the same time.

“We’re not sure if that is even a possibility at the moment, as we haven’t been able to find one that works that is still in the price range, and that still allows us to grow a suitable crop the next year.”

Mr Kaesler said his plan of management for the weed going forward is to “keep on top of them, keep checking them, and not letting them get away too much”.

“Currently, we’re trying to knock them with the blade during the summer when it’s really hot, and then getting (using machinery) to turn them up-side down so their roots are put out to the hot sun and burning them off,” he said.

“They still grow, as when you kill them, they release seed to try and survive, yet, these little ones you can hit harder with chemical and that has been successful, or at least seems to be.

“However, there is a give-and-take with this process as it compromises the soil structure. But, you really have no choice unless you want them taking over.

“We have also found that they don’t like competition, so getting the crop in early also helps. As this year was so wet, the crop did not suffer from the lack of moisture gazanias take out.

“However, if we have another dry year, gazanias will definitely take out the crop – and that’s the worst part.”