亚洲玉米螟的垂直分布

Vertical distribution of Ostrinia furnacalis

亚洲玉米螟在河北省张家口海拔1400 m以下地区均有分布。800 m以下地区是种群的主要分布区,以 500～600 m虫口密度最大。800 m以上发生程度一般很轻,其中个别地区因局部气候适宜,发生程度较为严重。同一海拔梯度内,水浇地与盆地的种群数量显著高于丘陵和旱地。不同寄主田内种群的分布比率,在海拔 800 m以下地区,玉米田高于谷子和高粱田,900 m以上地区谷子田明显高于玉米田。

Vertical distribution of Ostrinia fumacalis larvae was investigated in Zhangjiakou, Hebei Province. The population of Ostrinia fumacalis larvae was mainly distributed under 800 m a. s. 1. and its density reached the peak between 500 and 600 m a. s. 1. Above 800 rn a. s. 1., the population density was very small in numbers. At the same elevation, population densities of Ostrinia fumacalis larvae in the irrigated land and the basin fields were obviously higher than those in hilly and dry land. In different crop fields, the number of Ostrinia fumacalis larvae distributed in the cornfields was more than that in the millet or in the Chinese sorghum fields under 800 m a. s. 1. But above 900 m a. s. 1., number of the population in the millet fields was more than that in the cornfields.