田埂碱蓬带对棉田多异瓢虫种群发生的调控作用

【目的】 分析田埂碱蓬带对棉田多异瓢虫种群发生的影响,为合理利用非棉田生境实施棉蚜的生态治理提供科学依据。【方法】 采用田间种群系统调查和天敌控害功能罩笼评价。【结果】 田埂碱蓬带是棉田多异瓢虫的重要来源;有碱蓬带的棉田中多异瓢虫种群密度、多异瓢虫与棉蚜的益害比均高于没有碱蓬带的对照棉田,其中多异瓢虫平均密度是对照棉田的1.9倍、益害比是对照棉田的8.8倍;利用罩笼进行天敌隔离处理,第7和14 d处理组(封闭罩笼)棉花上棉蚜种群增长率均显著高于开放罩笼的对照组;有碱蓬带的棉田中捕食性天敌对棉蚜的控害指数显著高于对照棉田。【结论】 棉田田埂碱蓬带能有效增加棉田中多异瓢虫种群密度并提高益害比,对控制棉田棉蚜发生发挥着重要作用。碱蓬在天敌保育与控害中有重要作用,棉田周边予以留种。

Regulation and Control Effects of Suaeda Strips on the Population Occurrence of Hippomidia variegata in Cotton Fields

【Objective】 The study aims to examine the effects of Suaeda strips on the population occurrence of Hippomidia variegata in adjacent cotton field in the hope of providing a theoretical basis for the use of non-crop habitats adjacent cotton fields in enhancing efficient management of cotton aphid Aphis gossypii. 【Method】Systematic investigation and exclusive cage experiments were conducted in the fields. 【Results】 Suaeda strips were the important source of H. variegata in adjacent cotton fields. Both the population density of this predator and the ratio of enemy to aphid in cotton field adjacent suaeda strips were 1.9 times and 8.8 times higher than those in the cotton field without Suaeda strips, respectively. Exclusive cage experiment indicated that the relative growth rates of A. gossypii in caged treatment (i.e., without predators) were significantly higher than those in the open treatment (i.e., with predators) on the 7 th and 14 th days after trial. In addition, the biocontrol services index of predators to cotton aphid in cotton field with Suaeda strips was significantly higher than that in cotton field without Suaeda strips.【Conclusion】The study has shown that Suaeda strips in adjacent cotton fields could improve the abundance of H. variegata in cotton fields and increase the ratio of this key predator to aphid, thus playing an important role in suppressing A. gossypii. Therefore, when formulating the control strategy of cotton aphid, the important role of Suaeda salsa in the conservation and control of natural enemies should be fully considered, and it is suggested that the seed should be preserved around the cotton field.