X-ray radiation and developmental inhibition of Drosophila suzukii (Matsumura) (Diptera: Drosophilidae).

ABSTRACT

PURPOSE: Different doses of X-ray radiation were tested to assess the developmental inhibition effects on different stages of Drosophila suzukii, spotted wing drosophila (SWD). Efficacy of a potential quarantine treatment dose was evaluated for its practicality by a small scale-up validation test at a commercial facility. MATERIALS AND METHODS: X-ray treatments at different doses of 50, 100, 200, and 300 Gy were carried out with eggs, larvae, pupae and adults of SWD. The trial at the commercial facility was performed with pupae at 150 Gy. RESULTS: X-ray radiation inhibited development of all stages of SWD, and the estimated dose to cause 99% mortality or to prevent emergence (ED99) are reported here. Irradiation to eggs inhibited hatching, pupariation and adult emergence at 1962, 649 and 31 Gy, respectively. The inhibition of irradiated larvae to adult emergence was 66 Gy. Irradiation to pupae could not inhibit adult emergence completely even at 300 Gy. However, irradiation at 100 Gy and above induced complete adult sterility. Irradiation to pupae inhibited hatching of F1 eggs at 73 Gy, while for adults, total inhibition of F1 egg hatching was observed at 822 Gy. In the trial at the commercial facility, radiation at 150 Gy to pupae induced complete adult sterility in all combinations of cross-mating between treated or untreated males and females. CONCLUSION: This study suggests that X-ray radiation can be recommended as an alternative to methyl bromide as phytosanitary treatment for quarantine purpose.