Radiosensitivity of Different Immature Stages and Ages of Oriental Fruitfly, Dacus Dorsalis Hendel, to gamma Radiation

摘要

A study was conducted to determine the sensitivity of different ages of eggs, larvae and pupae of the oriental fruitfly to varying doses of gamma radiation. The most sensitive stage was the egg followed by the pupa and then the larva. Radiosensitivity of the eggs decreased as age increased from 2-3 to 28 hours during treatment. The LD 50 for younger eggs (2-13 hours) was less than 0.5 krad and for nearly mature eggs (18-28 hours) from 2.3 to 14.9 krad. Similarly with the larval stage, the LD 50 values increased with age of fruit flies at treatment. For 1-day-old larvae, the LD 50 was observed at 2.5 krad while for 7-day-old larvae, the LD 50 increased to 50 krad. Dosage required for 50% mortality in 1-day-old pupae was 1.4 krad and 32.1 krad for older pupae. Pupation was reduced to zero when 4-day-old larvae were exposed at 50 krad and 1-day-old larvae at 10 krad. More than 50 krad was required to prevent emergence of mature (7-day-old) pupae. The sex ratio of the emerging adults of D. dorsalis from the irradiated pupae assumed a 1:1 ratio. However, some adults had abnormally-developed wings upon emergence. Abnormality rates were greater when the pupae were treated young. Results indicate the feasibility of gamma radiation in the range of 40-50 krad for commodity treatments of fruits. (Atomindex citation 14:802148)