Sun damage risk of Royal Gala apple in fruit-growing districts in Australia

Abstract

This study estimated minimum air temperatures for potential sun damage for sunburn browning (non-netted and netted) and sunburn necrosis (non-netted) for Royal Gala apple in Australia. The approach estimated when conditions may be conducive to the development of sun damage in some fruit. The approach provides a measure of potential damage. This allows for more flexible analyses of potential sun damage which current models are unable to produce due to data limitations. The air temperature thresholds determined were 34.1 and 38.7 °C, respectively, for browning and necrosis for non-netted fruit and 37.9 °C for browning under netting. These air temperature thresholds were applied across southern Australia from 1911–2013 demonstrating different risk profiles between sites, inter-annual variability and the benefit of installing netting via a reduction in potential damage days. The results can be further extended to estimate impacts from climate change and assess the benefit of installing netting to adapt to increasingly extreme hot weather.