烟青虫和棉铃虫在陕西烟区的地理分布及其成因分析

Occurrence and Distribution of the Oriental Tobacco Budworm Helicoverpa assulta (Guenee) and the Cotton Bollworm H. armigera (Hubner) in Tobacco Field of Shanxi

调查表明，烟青虫Ｈｅｌｉｃｏｖｅｒｐａａｓｓｕｌｔａ（Ｇｕｅｎｅｅ）在陕西仅分布于关中和陕南；棉铃虫Ｈｅｌｉｃｏｖｅｒｐａａｒｍｉｇｅｒａ（Ｈｕｂｎｅｒ）虽在陕西各地烟田均有发生，但主要分布于陕北和关中。从地理上看，棉铃虫在陕北延安等地严重危害烤烟；在关中则主要危害烤烟留种田和晒烟留种株；在陕南发生极少，仅开花后在花上有少量幼虫。从生育期上看，在两种害虫混发的关中地区，团棵至旺长期主要是烟青虫，而棉铃虫仅在干旱的渭北旱塬上发生，开花后则逐渐过渡到棉铃虫为主，９月以后留种田发生的全为棉铃虫。推测棉铃虫起源于北方干旱地区，烟青虫则起源于湿润的东洋区。讨论了这两种夜蛾分布区差异以及造成中关烟田早、中晚期区系组成差异的原因。初步提出了烟青虫和棉铃虫在陕西当地蜜源植物间转移的可能规律．并提出了防治对策的建议。

The geographical distributions of the Oriental Tobacco Budworm (OTB), Helicoverpa assulta (Guenee ), and the Cotton Bollworm (CBW ), Helicoverpa armigera (Hubner), two notorious leaf-eating and fruit-boring insect pests on tobacco, were investigated in Shanxi Province. The results show that OTB is distributed in south and central Shanxi with its north limit roughly at the south margin of the Loess Plateau and mainly feeds on the tender leaves of tobacco. Although it occurs all over the province,CBW is mainly distributed in north and central Shanxi, generally feeds on tabacco leaves in north Shanxi, and mainly attacks the flowers and fruits of tobacco in central Shanxi.TBW is supposed to be originated from the humid Oriental Region, And CBW might evolve in the arid Palearctic Region. The mechanisms of the comparative abundance of CBW and TBW and their migration among flowering host plants between seasons are discussed. The control measure is also proposed.