Minor changes leads to better spray coverage at Moora Citrus
30 January 2019
Roland Hessels says making minor changes to his spray set-up after attending a course run by NSW DPI in Dareton has seen significant improvement in coverage.
The main purpose of the workshop was to provide growers with the skills and knowledge to test the performance of their spray machines and to understand the options they have to improve this.
On the day, it was explained how different types of commonly used citrus spray machines have different attributes.
These contribute to good air movement within the trees and the various fan configurations.
Workshop organiser Steven Falivene, NSW DPI, demonstrated how to test nozzle outputs and to quickly calculate litres per ha volume application rates.
The importance of pre-season and pre-spray maintenance and checks was highlighted, with the options available for adjusting spray machines
for optimum performance was also discussed.
Mr Hessels is the spraying manager at Moora Citrus, Moora, WA. He and his
team assessed their program and made minor changes, which has improved coverage.
“We changed the direction of the fan heads to ensure they don’t cross,” he said.
“We have also set up now so we don’t have a gap between fans and cover every part of the tree. As an example, if you have three 75cm fans, and you want
to spray three metres, you’re going to have a gap.”
The Moora Citrus team replicated a trial from the field day, with help from Elders and Sacoa, putting kaolin clay in the spray tank. This enabled them to see what they were missing.
“It’s quite an eye opener when you do that,” Mr Hessels said.
“We use Surround and found we needed to adjust the angle and position of fans. We now know for sure we’re getting into the trees and the coverage is there.
“It has reassured us we’re doing the right thing.”
On the day Moora citrus replicated the trial from NSW, local growers were invited to look at the results. Ultra Violet dye was also used at different spray rates and on different tree sizes.
Mr Hessels said an interesting outcome of this trial was the amount of run-off on the smaller trees.
“We use Du Wett to enable us to reduce our spray rates, but we found we didn’t need it in the smaller canopy sizes,” he said.
Pruning has also been important in maximizing spray coverage.
“Last year we opened up the canopy to encourage light inside. The spray couldn’t get past the big branch and inside the tree as it was too bushy.”