| Effects of gamma irradiation on the biology and reproduction of Helicoverpa armigera Hübner |
| Paper ID : 1187-3IICE (R2) |
| Authors: |
|
Shiva - Osouli *1, Mehrdad Ahmadi2, Nadia Kalantarian3 1Nuclear Science and Technology Research Institute, Nuclear Agriculture Research School, Karaj, Iran 2Nuclear Science and Technology Research Institute 3nuclear agriculture research school |
| Abstract: |
| Helicoverpa armigera Hübner (Lepidoptera: Nuctuidae), is one of the most important pests in the world. It is usually controlled by frequent application of persistent pollutant chemicals. As an environment-friendly alternative, the sterile insect technique (SIT) is applied as a component of area-wide integrated pest management (AWIPM) programs against several major insect pests. The SIT involves rearing large numbers of the target species, exposing them to ionizing radiation to induce sexual sterility, and releasing them into the target population. The released sterile males mate with wild females to prevent them from reproducing. In this research the effects of different doses of gamma irradiation in the range of 150 to 350 Gy on some biological parameters of H. armigera were evaluated. The larvae were reared on a modified artificial diet. Pupae were harvested after about 15 days irradiated 8 days after. The emerged adults were paired in oviposition cages in certain combinations and allowed to mate and lay eggs. The mean percentage of pupal mortality increased 11.67% with increasing doses to 350 Gy when 8 day-old pupae were irradiated (27.67% at 350 Gy compared to 16% in the control). The lifespan of male and female H. armigera irradiated in the pupal stage, were significantly shortened. The male longevity was 17.28, 16.58, 14.44, 12.21, 12.45 and 12.47 days and for adult female was 17.21, 15.18, 14.30, 12.28, 12.31 and 12.34 days at the doses of 0, 150, 200, 250, 300 and 350 Gy, respectively. The sex ratio of emerged adults skewed to the females with increasing doses (proportion of females to all adults was 0.55 and 0.64 at 300 and 350 Gy, respectively, compared to 0.51 in the control). The female fecundity was remarkably affected by radiation in all following crosses: irradiated male × normal female, normal male × irradiated female, irradiated male × irradiated female and were 6.77, 2.00 and 1.43 at 350 Gy, respectively compared to 793.10 in control. The percentage of hatched eggs reached 0 at 350 Gy in various reciprocal crosses, while this value was less than 4% when normal males mated with irradiated females at 300 Gy. The percentage of hatched eggs was 16.85%, 3.41% and 23.16% at the dose of 300 Gy in reciprocal crosses respectively, compared to 71.60% in the control. Based on the results, the dose of 350 Gy could be suggested as the proper sterilizing dose for this pest. |
| Keywords: |
| Sterile Insect Technique (SIT), Helicoverpa armigera, Gamma Irradiation, Radiobiology, Fecundity, Fertility |
| Status : Paper Accepted (Poster Presentation) |
