Testing GA3 on bearing apple trees

August 2016 | Stephen Tancred | Future Orchards® trial final report, Stanthorpe, Queensland

This Future Orchards® trial tested gibberellic acid (GA3) as a tool for stimulating vegetative growth in bearing apple trees in Stanthorpe. The work was designed to move beyond a simple treated-versus-untreated comparison and examine practical application choices that could influence response in commercial orchards.

The trial compared GA3 rates of 300 and 400 ppm, investigated whether wetters improved efficacy, compared three, four and five applications, and considered different application methods. Applications began in late October 2015, with growth measurements through December, January and March and the trial inspected during the January 2016 Orchard Walk.

The report is useful for growers considering whether GA3 can support canopy development in bearing trees while still fitting normal orchard operations. It emphasises that rate, application frequency, additives and application method all need to be considered rather than assuming a single GA3 program will perform consistently across blocks.

The final report was submitted on 4 August 2016 and documents the trial objectives, treatment structure and observations from the Stanthorpe demonstration.