Enhancing Red Fruit Coloration of Apples in the Southeastern US with Reflective Fabrics

For some apple cultivars, inadequate red fruit color development can reduce crop value. The use of reflective groundcovers has been demonstrated to improve red coloration in apples in other regions, but evaluation in the southeastern USA has been limited. To address this, we compared the performance of multiple reflective groundcovers in 2018 and 2020 on mature ‘Fuji’ trees in Edneyville, NC, USA. Woven reflective (Extenday® DayBright, Lumilys® WH100, Beltech PD2911, and Belton experimental), mylar, and sod groundcovers were deployed ~5 weeks before anticipated harvest. The effects of the treatment on light reflectance (photosynthetically active and UV radiation), fruit color, fruit quality, and crop value were determined. Across both years of evaluation, reflective groundcovers were consistent in increasing the reflectance of photosynthetically active radiation. However, only Extenday® DayBright consistently increased reflected UV radiation (250–400 nm), red fruit coloration at commercial harvest, and crop value. Fruit maturity and sunburn incidence were not influenced by any treatment in both years. Reflected UV light quality was not characterized, but it is clear that UV250–400nm reflectance intensity is critical to enhance ‘Fuji’ fruit color development. Growers in the southeastern US can use reflective groundcovers to enhance red fruit coloration to meet market demands.