Effects of γ-irradiation as phytosanitary treatment on the quality of Japanese fruits and the survival of their regulated pests

Abstract

Irradiation with γ-rays, electron beams, and X-rays was a widely accepted plant quarantine treatment, and the International Standards for Phytosanitary Measures (ISPM) have been gradually prepared against regulated pests. The effective doses against these pests for phytosanitary irradiation were recently admitted as new annexes in ISPM No. 28. In Japanese fruits, the peach fruit moth and Japanese orange fly commonly become the causes of severe issues in exporting apples and Satsuma mandarins from Japan. Therefore, the species-specific dose for peach fruit moth and the generic dose for the family Tephritidae were administered to confirm the effectiveness of irradiation treatments to prevent the adult emergence of these pests. Moreover, depending on the dose level, the fruit quality might be affected by irradiation, although different fruit cultivars might show different responses. The responses of apple and Satsuma mandarin cultivars in Japan should be clarified to determine applicability of irradiation treatments. Preliminary assessment on Japanese cultivars of 11 kinds of apples and 3 mandarins were investigated in this report. In conclusion, phytosanitary irradiations are effective against two pests in apples or Satsuma mandarins while keeping high quality as the commodity.