Abstract:

The number of eggs of Helicoverpa armigera directly affects the number of larvae which harm the cotton. However, generation two of H. armigera do the severe harm to cotton in Xinjiang. There are differences on climate and soil types among different cotton-planted areas. Soil is important intermedium for larvae to enter soil and pupate and has affected on promoting eggs. Thus, it has theoretic and practical significance that we understand what function of the soil will bring on the eggs. In this study, long term data on H. armigera from two plant stations in south (Maigaiti county) and north (Shawan county) of Xinjiang and experiment data from 30 agricultural meteorology experimentation stations in Xinjiang were employed to conduct path analysis, clustering analysis and regression analysis. The results showed that there were more influence factors on eggs of H. armigera in Maigaiti county than that in Shawan county. Soil bulk density had litter direct effect on eggs of H. armigera in Maigaiti county (-0.025) than that in Shawan county (-0.294). The indication effect of soil bulk density on occurrence of eggs of H. armigera to the north of Xinjiang was more evidence than that to the south of Xinjiang. The effect of precipitation on H. armigera was different in south and north of Xinjiang. The effect of soil bulk density on eggs of H. armigera was negative and it could have indication effected in some extend. So it can be regarded as indication effect in some extend on occurrence of eggs of H. armigera when use soil bulk density in different regions and combine weather and biological factors.