转Bt基因抗虫棉和常规棉田主要害虫与天敌种群数量的比较

以常规棉苏棉16、渝棉1号和转Bt基因抗虫棉科棉1号、科棉4号为试验品种,调查了初花期和盛花期2种类型棉田主要害虫和天敌的种群数量。结果表明,2种类型棉田初花期和盛花期害虫发生量不同,但趋势基本一致,即转Bt基因抗虫棉棉田棉铃虫、棉红铃虫和棉大卷叶螟等鳞翅目害虫的发生量明显低于常规棉品种,表现出良好的抗性;棉叶蝉和棉盲蝽等非鳞翅目害虫的发生量在不同类型品种间无显著差异;2种类型棉田害虫的主要差别是非鳞翅目害虫。研究结果还表明,鳞翅目害虫的发生和赤眼蜂、瓢虫等天敌的发生间有一定的追随关系。针对不同类型棉田应有不同的防治策略,常规棉主要是进行鳞翅目害虫的防治,兼顾非鳞翅目害虫;抗虫棉棉田害虫的防治以非鳞翅目害虫为主,以免其取代鳞翅目害虫成为主要害虫。

Characteristics of Major Pests and Predations of Conventional Cotton and Bt. Transgenic Cotton at Early and Full Flowering Periods

With conventional cotton cultivar-Sumian 16 and Yumian 1, Bt transgenic cotton cultivar-Kemian 1 and Kemian 4 as the testedmaterial, the populations of major pests and predations at early and full flowering periods were investigated. The main results were as follows: theincidence trends of major pests and predations were similar at early flowering period and full flowering period in spite of different incidencequantity. The number ofHelicoverpa armigera, Sylepta derogata, Empoasca biguttula and Pectinophora gossypiella per 100 plants in Bt transgeniccotton field was significantlylower than that in conventional cotton field. There was nosignificant difference in the number of Empoasca biguttulaand Lygus lucorum between transgenic cotton field and conventional cotton field. The incidences of Lepidoptera pests and major predationsincluding ladybird beetles and Trichogrammatidae were closely positively correlated. Different control techniques of pest must be adopted intransgenic cotton field and conventional cotton field.