Determination of the Optimum Sterilizing Dosage for Pink Bollworms Treated as Pupae with Gamma Radiation2

Abstract

The effect of gamma radiation from cobalt-60 on pupae and adults of the pink bollworm, Pectinophora gossypiella (Saunders), following pupal exposure was determined. Pupal sensitivity to gamma radiation was dependent on age at time of treatment the older the pupae, the Iess susceptible they were. When 1-and 3-day-old pupae were irradiated, dosages inducing complete sterility also caused some pupal mortality and appreciable moth damage; however, irradiation of 5- or 7-day-old pupae induced almost complete sterility without pupal mortality or adult malformation. When males from irradiated 7-day-old pupae were mated with untreated females, complete sterility was achieved at 55 kr, and within the range of 30 to 60 kr, no more than 3% of the oviposited eggs hatched at anyone exposure dosage. Exposure at 40 kr was sufficient to sterilize females. Longevity of males from 7-day-old pupae treated with 35 through 90 kr was significantly shorter than that of the control.