The Efficacy of Four Sunburn Mitigation Strategies and Their Effects on Yield, Fruit Quality, and Economic Performance of Honeycrisp Cv. Apples under Eastern New York (USA) Climatic Conditions

Abstract

Sunburn is a serious economic problem in practically all apple-growing regions of the world. Losses of apple fruit due to sunburn can range from 10% as high as 50%. Several years ago, this problem started to be a concern in Eastern New York State, especially in the Hudson Valley region with the cultivar ‘Honeycrisp’. The study was conducted in three ‘Honeycrisp’ apple tree orchards in the Hudson Valley region (Southeast, New York State) during the 2015 and 2016 growing seasons. Four sunburn mitigation strategies were tested (evaporative cooling, 20% crystal net, the sunscreen Raynox Plus® and the particle film ScreenDuo®) at a variety of timings throughout each growing season. Yield, sunburn incidence/severity, quality, and economic returns were evaluated. Treatments did not affect horticulture performance and fruit quality, but they did reduce sunburn damage to varying degrees. The greatest sunburn mitigation was achieved with the use of netting, followed by spray applications of Raynox Plus® and ScreenDuo®. Apples with sunburn damage had higher flesh firmness, soluble solids content and titratable acidity. Treatment differences in sunburn mitigation did not result in higher net returns to the grower.