Effect of blocking pest stings and solar radiation on rind-stain development in ‘Encore’ mandarin fruits

Mandarins are popular in the global fruit market due to their convenience and health benefits. ‘Encore’ is a late mandarin cultivar, which allows the harvesting season of fresh mandarins to be extended.
This mandarin is valued for its sweet flavor and distinct aroma but faces a pre-harvest rind stain problem, which affects acceptance in some markets.
These rind stains may result from solar radiation exposure or physical damage, such as pest punctures.
To investigate the effect of these factors, an experiment was set up with different types of bags: translucent bags, which block insect access to the fruit, and opaque, which also protect the fruit from solar radiation; comparing both to uncovered fruits.
The rind stain severity and incidence were similar in fruits covered with translucent bags and those uncovered, suggesting that pests do not cause the spots.
In contrast, opaque bags reduced rind stain severity and incidence but did not eliminate them, indicating that exposure to sunlight worsens rind stain without being the primary cause of this physiological disorder.
Overall fruit quality was similar across treatments, except for those in opaque bags, which had lower total soluble solids and a lower maturity.

XV International Citrus Congress

P. Matias, B. Duarte, A.R. Trindade, A. Duarte

Citrus ×nobilis, Citrus ×deliciosa, external appearance, fruit spots, fruit blemishes, sun exposure

https://doi.org/10.17660/ActaHortic.2026.1448.55