The medium rainfall zone of South Australia’s Eyre Peninsula presents grain growers with a double challenge: Firstly, reasonably reliable seasonal rainfall increases fungal pressure in most crops; and secondly, the peninsula juts into the Southern Ocean alongside the Great Australian Bight, meaning wind is a constant presence.

Those conditions make spraying a necessity and a challenge. However, local grower and operator Corey Murnane found the solution back in 2004 and he’s been using the HARDI TWIN air assisted spray system ever since.

Today, he is up to operating his fourth HARDI TWIN machine, a 4,200 litre HARDI ALPHA evo II self-propelled sprayer with 30,5 metre TWIN FORCE boom.

Corey sprays 8,500 hectares in a mix of wheat, barley, canola, beans, lentils and lupins.

Rainfall for the area averages about 400 mm per year, meaning Corey has to keep on top of regular fungicide applications to control a range of pathogens, along with herbicide treatments to control weeds from before sowing until the crops begin to mature. He also adds trace elements to his wheat crop throughout the growing season.

“I rely on the TWIN boom for canopy penetration as well as greater control over spray timing,” he says.

“As the crops develop, I increase the air volume to push the fungicide right down to the lower leaves.

“At sowing the air volume will be in the 40% to 50% range, increasing to 60% and then 80% as the plants grow and fill out.

“By the time I do my last spray of the season in October, I’ll bring the air volume right up to 100% to make sure the fungicide and trace elements are getting through to where they’re needed.”

Corey also takes full advantage of the way the TWIN system lets him keep spraying in windier conditions, so that he can keep to his fungicide application schedule.

“The air really helps me keep control of the spray in difficult conditions,” he says.

“On windy days I’ll bring the air angle right forward to 15º to make sure the spray is pushed into the crop without any interference and control drift.”

This allows him to spray at a consistent 1.6 Bar pressure, using 05 FF nozzles and a forward speed of 22 kilometres per hour.

While the highly effective penetration and accuracy of the TWIN system makes it possible for growers to reduce water consumption and chemical usage, Corey sprays at label rates. 

“The advice from my agronomist at Cummins Ag is to follow the label recommendations,” he says.

“For me, the TWIN system is all about drift control, so I can spray fungicides at the times they’re needed.”

Corey uses the TWIN FORCE ALPHA evo for all his fungicide applications. However, he also uses a HARDI SARITOR self-propelled sprayer for herbicide and pesticide and appreciates the weight difference between the two sprayers.

“You can see how much lighter the ALPHAs are,” he says. “Lightness is a very good quality in a sprayer.”

Having had four ALPHAs with TWIN air systems over the past 15 years, Corey is unable to fault them. In fact, his next sprayer is likely to be a 5100 litre ALPHA evo II.

“There are a couple of new machines with the 5,100 litre tank in the area now and I’ve heard they’re still fairly light,” he says.

“I’d definitely give one of those a shot.”