ABSTRACT
The sterility effects were examined on the P1 generation of the black cutworm; Agrotis ipsilon (Hufn.) after gamma sterilization. Our objective was to identify the dose of gamma radiation that would allow for maximum production of partially sterile P1 adults while inducing full sterility in the F1 generation. Full grown pupae of the black cutworm from laboratory culture were irradiated at 0, 75, 100,125, 150,175 and 200 Gy. Results indicated that no significant difference between untreated and treated groups in moth were observed in copula occurred, nor time of copulation ,while significant difference were recorded between the treated males and untreated once in spermatophore formation and percentage of females with sperm in their spermatheca. Lower percentages of untreated female moths were mated when they were paired with previously mated males than when paired with virgin males. The sequence in which females were mated to an irradiated male did not affect the transfer of spermatophores. However, the percentage of eggs hatched was higher from the first mated female compared to the second and third mated female. There were no significant effects of 0 or 125 Gy exposures on female mating or time in copula. However, significantly lower percentages of mating of treated and untreated females occurred with sequentially provided male moths on days 2, 3, to 5 following the first observed female mating. Mating competitiveness was measured from direct observations at all doses ,the males treated up to 125 Gy were full competitive to untreated male
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