两种蚜小蜂对烟粉虱MED隐种的田间笼罩控效评价

为明确烟粉虱Bemisia tabaci MED隐种优势寄生蜂海氏桨角蚜小蜂Eretmocerus hayati ZolnerowichRose与浅黄恩蚜小蜂Encarsia sophia GiraultDodd对其控制效果的影响,在棉田尼龙纱网笼罩中释放烟粉虱之后,再分别单独释放海氏桨角蚜小蜂、浅黄恩蚜小蜂以及二者以不同比例组合(1∶1、1∶3、3∶1)释放,定期调查统计2种蚜小蜂对烟粉虱的寄生量和烟粉虱的种群动态。结果表明,相对于不放蜂对照,自首次放蜂后40 d开始,所有放蜂处理均能显著降低烟粉虱若虫种群密度,每100 cm~2叶片上均少于1.00头,但各处理间的烟粉虱种群密度无显著差异;海氏桨角蚜小蜂和浅黄恩蚜小蜂以3∶1比例组合释放的处理中对烟粉虱的寄生量最高,每100 cm~2棉花叶片上能达到4.25头。表明在棉田中对烟粉虱进行生物防治时,以初级寄生蜂海氏桨角蚜小蜂与复寄生蜂浅黄恩蚜小蜂为3∶1的比例释放,可以到达较好的控制效果。

Field cage evaluation of the biocontrol effect of two aphelinid parasitoids on Bemisia tabaci Mediterranean (Hemiptera: Aleyrodidae)

To explore the sustainable management of Bemisia tabaci (Gennadius) Mediterranean and better understand the biological control effects of single and multiple releases of parasitoid species, the performance and interaction of two aphelinid parasitoid species of B. tabaci, Eretmocerus hayati Zolnerowich & Rose and Encarsia sophia Girault & Dodd were evaluated. Single species release and two species combined released (in 1:1, 1:3 and 3:1 density ratio) were conducted in field cages on cotton. The population dynamics and parasitism on B. tabaci were regularly sampled after the releases. The results showed that, 40 d after the two wasps were firstly released, all parasitoid releases successfully reduced the densities of B. tabaci nymphs (less than one nymph per 100 cm² cotton leaves) compared to the control, and there were no significant difference in the densities of B. tabaci nymphs among treatments; the combined release of two parasitoid species (Er. hayati and En. sophia) at the ratio of 3:1 showed the highest parasitism of B. tabaci nymphs at 4.25 per 100 cm² cotton leaves. Therefore, the combined release of the primary parasitoid Er. hayati and the autoparasitoid En. sophia at the ratio of 3:1 in the cotton field is recommended for control of B. tabaci.