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ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Crop and Commodity Protection Research » Research » Publications at this Location » Publication #423225
Research Project: Postharvest Protection of Tropical Commodities for Improved Market Access and Quarantine Security

Location: Tropical Crop and Commodity Protection Research

Title: Tolerance of four New Zealand apple cultivars to disinfesting x-ray treatment

Author
item CHO, JUNG - New Zealand Institute Of Plant & Food Research
item Postler, Melissa
item ORTIZ, GUINEVERE - New Zealand Institute Of Plant & Food Research
item Villalun, Maryann
item HALL, MIRIAM - New Zealand Institute Of Plant & Food Research
item REDPATH, SIMON - New Zealand Institute Of Plant & Food Research
item WOHLERS, MARK - New Zealand Institute Of Plant & Food Research
item JAMIESON, LISA - New Zealand Institute Of Plant & Food Research
item Follett, Peter
item Wall, Marisa
item WOOLF, ALLAN - New Zealand Institute Of Plant & Food Research

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2025
Publication Date: 1/20/2026
Citation: Cho, J., Postler, M., Ortiz, G., Villalun, M., Hall, M., Redpath, S., Wohlers, M., Jamieson, L., Follett, P., Wall, M., Woolf, A. 2026. Tolerance of four New Zealand apple cultivars to disinfesting x-ray treatment. HortScience. 61(2):403–408. https://doi.org/10.21273/HORTSCI18962-25.
DOI: https://doi.org/10.21273/HORTSCI18962-25

Interpretive Summary: Radiation is an effective quarantine treatment for global trade of fresh produce. The quality and ripening of diverse fruit cultivars can affect sensitivity to radiation treatment, and ultimately consumer acceptance. This study examined the impact of a range of X-ray doses on the fruit quality of four apple cultivars for the purposes of quarantine security. Higher doses resulted in lower fruit firmness for all cultivars compared to untreated controls. Internal browning was the only quality disorder observed in X-ray treated fruit and only for Royal Gala fruit at 700 Gy and higher. Given that internal pests will be controlled by doses of 200 Gy, X-ray ionizing radiation may be a valuable tool for phytosanitary quarantine treatment of apples.

Technical Abstract: While external quarantine pests can be controlled postharvest by fumigation or removal (e.g. pressure washing), internal pests (in particular codling moth; CM) are difficult to control and can be a significant market access issue. X-ray ionizing radiation has the potential to sterilize internal pests such as codling moths and doesn’t involve using a radioactive source. This study sought to examine the effect of a range of X-ray doses on the fruit quality of New Zealand-grown apple cultivars – ‘Royal Gala’, ‘Fuji’, ‘Scired’ and ‘Scifresh’. Fruit were harvested and packed commercially in New Zealand and transported to Hilo, Hawaii, for X-ray treatment at 150, 300, 500, 700, 1000 and 1400 Gy. Following X-ray treatment, fruit were stored at 0.5 °C for eight weeks and assessed after seven days at 20 °C. Higher X-ray doses resulted in lower fruit firmness for all cultivars compared to untreated controls, although significant differences did not occur until doses of 500 to 700 Gy. There were only minor to no significant effects on total acidity, soluble solids or skin color. Regarding visual damage symptoms, internal browning was the only quality disorder observed in X-ray treated fruit and was only significant in ‘Royal Gala’ fruit at 700 Gy and higher. Internal browning was not observed in any other cultivars. Given CM will be controlled by doses of ˜ 200 Gy, X-ray ionizing radiation may be a valuable tool for phytosanitary quarantine treatment of New Zealand apples.