The Research On Hardiness Characteristics Of The Overwintering Generation Of Helicoverpa Armigera (Lepidoptera:Noctuidae) In North China

Helicoverpa armigera is a kind of serious agricultural pest with a widely host in the world. Different host has different influences to the biological characteristics and hardiness characteristics of H. armigera. Under the situation of actual agricultural landscape consisting of Bt cotton and corn in the north China, the hardiness characteristics of overwinter generation of H. armigera eating different hosts was studied in this paper.Firstly, four of main hosts in north China were fen on Helicoverpa armigera to explore the influence of eating different hosts for it. The results showed that larval stage, pupae stage, pupae weight, pupation rate, eclosion rate, male and female proportion of H. armigera were different among fed on Bt cotton, corn, wheat and sorghum host.Then the influence of hardiness characteristics of eating different hosts for overwintering H. armigera was further studied in this paper. We have simulated overwintering situation in filed and fed H. armigera on fresh hosts. It was found that the diapausing pupae of H. armigera feeding on corn had obviously higher dry weight, fat content and trehalose content, and lower freezing point than the diapausing pupae fed on Bt cotton. The results indicated that corn is the ideal host for H. armigera to live through the winter in the field.In order to test the result, we get overwintering generation of H. armigera with poplar trap in field in the following April and May and traced the source of larval stage's food in the last year by stable isotope analysis. The result showed that H. armigera came from C4 plant (corn) is more than that came from C3 plant (Bt cotton) and female was more than male. It was indicated that eating corn was better than Bt cotton for resisting hardiness of H. armigera.According to the historical data, the planting area of corn has been increasing in recent years, which will facilitate the successful overwintering and population expansion of H. armigera. Therefore, it is important to manage H. armigera in cornfield.