[en] The Symposium held in Athens, Greece, from 14 to 18 September 1970, jointly organized by the International Atomic Energy Agency and the Food and Agriculture Organization of the United Nations, was attended by 89 participants from 39 nations and representatives of six international organizations. The Symposium was held against a background of mounting interest and concern throughout the world with regard to the relative merits and economy of various methods of insect control to protect agricultural production and public health. There was general agreement that continuing reliance on pesticides for insect control has numerous disadvantages. However, there was also a clear-cut appreciation that while alternative methods of insect control are drastically needed they have not been developed to an extent that they can be immediately implemented in previously pesticide-oriented insect control programs. (author)

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[en] Adult males of the pink bollworm, Pectinophora gosypiella (Saunders), were irradiated with 19 and 30 krad of gamma radiation and mated with virgin, untreated females. Males treated with 19 or 30 krad of gamma radiation, at 2 to 24-h or 48 to 72-h postemergence, respectively, did not show reduced mating frequency compared with the untreated male controls. However, transfer of eupyrene sperm was reduced by treating 2 to 24-h postemergent males with 30 krad. Irradiation with 19 or 30 krad did not cause complete male sterility; 12.7 and 16.8 percent, respectively, of the fertilized eggs hatched. Eggs fertilized with irradiated sperm were examined cytologically and showed a retardation of embryonic development up to the blastoderm stage. From the blastoderm stage onward, development was parallel to those eggs which were fertilized by unirradiated sperm. Of the embryos in the groups treated with 30 and 19 krad, 51.3 to 66.6 percent, respectively, developed into fully differentiated, normal-appearing, prehatch embryos. The radiation-induced dominant lethal mutations were, generally, expressed very late in embryonic development

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[en] Males of Pectinophora gossypiella (Saunders) were treated with 20 krad of gamma irradiation at 2 or 3 days postemergence and then placed with 1 virgin female every 24 h for 4 consecutive transfers. Mating, amount and kind of sperm received, egg production, and egg hatch were recorded for each female. In this manner, we could determine whether a male mated with all 4 or fewer than 4 females and whether the 1st ejaculate occurred with the 1st or a subsequent female and could compare the results with oviposition and hatch records. There was no significant difference in the frequency of mating between irradiated and control males: 85% of control males mated an avg of 2.4 times; 83% of treated males mated an avg of 2.2 times. The 1st and 2nd matings were similarly distributed in both groups of males. However, there was a highly significant difference in the 3rd mating; 63% of the control males mated for the 3rd time with the 3rd female, compared to 33% for the irradiated males. Both irradiated and control males transferred similar amounts of eupyrene sperm in the 1st ejaculate. The amount of sperm received was significantly lower in subsequent ejaculates, and was significantly lower in females that mated with irradiated males than in those that mated with control males. The 1st ejaculate by either control or irradiated males elicited a greater ovipositional response than subsequent ejaculates, but irradiated males did not elicit as great an ovipositional response as control males. There was no significant difference whether the 1st ejaculate occurred with the 1st female or with females 2-4. We found a significant reduction in hatch of eggs fertilized by irradiated sperm, but there was no significant difference in egg hatch in females that received any of the ejaculates from an individual male