Irradiation to ensure quarantine security for Cryptophlebia spp. (Lepidoptera : Tortricidae) in sapindaceous fruits from Hawaii

Studies mere undertaken to determine whether irradiation treatment at 250 C y, an accepted treatment for disinfestation of fruit flies in spindaceous f ruits from Hawaii, would also disinfest fruit of two species of Cryptophleb ia. Cryptophlebia illepida (Butler) was determined to be more tolerant of i rradiation than Cryptophlebia ombrodelta (Lower): therefore, C. illepida wa s the focus for detailed tests. Using the criterion of success in developin g to the adult stage, the pattern of tolerance to irradiation in C. illepid a was generally eggs < early instars < late instars < pupae. The most toler ant stage potentially occurring in harvested fruits was late (fourth and fi fth) instars. Development to adult was reduced slightly in late instars rec eiving an irradiation dose of 62.5 Gy, whereas development to adult was dra matically: reduced in late instars receiving irradiation doses <greater tha n or equal to>125 Gy. No C. illepida larvae receiving an irradiation dose g reater than or equal to 125 Gy emerged as adults and produced viable eggs, indicating sterility can be achieved at doses well below 250 Gy. In large s cale tests, when 11,256 late instars were irradiated with a target dose of 250 Cy, 951 pupated (8.4%) and none eclosed as adults. Within the pupal sta ge, tolerance increased with age; 7- to 8-d-old pupae (the oldest pupae tes ted) treated with an irradiation dose of 125 Gy produced viable offspring, whereas those treated with a dose of 250 Gy produced no viable offspring. I rradiation of adults with a target dose of 250 Gy before pairing and mating resulted in no viable eggs. Irradiation of actively ovipositing adult fema les resulted in no subsequent viable eggs. Therefore, the irradiation quara ntine treatment of a minimum absorbed dose of 250 Gy approved for Hawaii's fruits will effectively disinfest fruits of any Cryptophlebia in addition t o fruit flies.