【作者】 孟昭军；

【导师】 张帆； 孙庆田；

【作者基本信息】 吉林农业大学 ， 农业昆虫与害虫防治， 2003， 硕士

【摘要】 2001和2002年在河北省南皮棉区，对不同类型棉田(转Bt基因棉田、常规对照棉田)和不同防治措施(Bt综防田、Bt化防田)的棉田，以及棉田周边生境的生物群落进行了系统的调查，将常规棉田、Bt综防田、Bt化防田的生物多样性、抗虫性，以及棉田周边生境中节肢动物的种群动态等进行了研究，主要结果如下： 1 棉田共查到节肢动物17目69科147种，其中害虫32科61种、中性节肢动物10科17种、天敌34科69种。天敌中其中瓢虫类6种、蜘蛛类11科26种、捕食蝽类5科5种、草蛉类3种、寄生蜂类9科18种。 2 不同棉田节肢动物多样性比较分析表明，转Bt基因棉田与对照常规棉田物种、功能团和亚群落的多样性、优势度、均匀度均无显著性差异。采取综防措施后的Bt棉田，棉田节肢动物物种、功能团、亚群落的多样性、均匀度显著提高，优势度显著降低；而害虫亚群落丰富度显著降低，中性和天敌亚群落的丰富度显著增高。7月份是棉田节肢动物种群增殖、群落重建的重要时期，此期减少棉田用药，采取综防措施保护利用棉田天敌，能显著增强棉田天敌的控害效能，弥补转Bt基因棉抗性逐渐下降的不足，提高棉田生态系统的稳定性。 3 对棉田周边生境生物多样性的调查结果表明，棉田周边的小麦田、杂草区、玉米田等非作物生境对棉田天敌群落恢复和重建发挥着天敌种库的作用。5月下旬至6月初，麦田大量天敌迁入棉田，田间益害比增加，控害能力极强，但不久由于棉田生境的不适，6月下旬大量天敌又迁出棉田。7月初至8月上旬，棉田伏蚜的迅速增殖，春玉米田、杂草区、枣树等周边非作物生境中的天敌大量迁入，开始天敌种群恢复及群落的重建。8月中旬以后，虽然棉蚜数量迅速减少，但棉蓟马、烟粉虱、棉叶蝉的种群数量猛增，捕食性天敌保持着较稳定的种群数量。 4 转Bt基因棉的田间抗性研究表明，转Bt基因棉对棉铃虫的田间着卵量无显著影响；各代棉铃虫幼虫的田间残留量比常规对照棉田显著降低，二、三、四代棉花被害率显著降低，说明抗虫棉的抗虫性较高，效果明显；由于转Bt基因棉对棉铃虫的杀虫活性存在明显的时间差异和器官差异，抗虫性表现为二代棉铃虫发生期抗性显著，三、四代抗性减弱，化防转Bt基因棉棉田于三、四代棉铃虫发生期需喷药3-4次扫除残虫，而此期综防棉田释放赤眼蜂，压低了棉铃虫卵基数，弥补抗虫棉抗性减弱的不足，又减少田间用药，保护并增殖棉田天敌，从而加强了天敌的控害作用。 5调查表明，绿盲椿已成为河北省南皮棉区的主要害虫。在该地区，该虫一年发生三代，第一代于6月下旬一7月初迁入棉田，而后在棉田继续繁殖2个世代，于9月下旬产卵于棉花、杂草、树木等的枯枝、残叶内越冬。绿盲椿在田间呈聚集型分布。严重危害棉田，棉株被害率达92%~98%，棉叶被海率达12.。一3 0 .9%。棉田绿盲椿优势捕食性天敌功能团发生数量较高，发生期内不同棉田平均百株虫量分别为:瓢虫类40 .6一93 .8头，捕食蜷类14 .13一65 .43头，草玲类2 .1一13 .7头，蜘蛛类19 .8一29 .9头。用生态位重叠度指数分析表明，各功能团对绿盲椿的控制作用大小顺序为:捕食椿类>瓢虫类>草岭类>蜘蛛类;用捕食性天敌控制作用指数计算表明，各功能团对绿盲椿的控制作用大小顺序为:瓢虫类>捕食蜷类>草岭类>蜘蛛类。两个分析结果虽然不完全相同，但控制作用的大小趋势相当，均表明了捕食蜷类和瓢虫类是棉田控制绿盲堵能力最强的两大天敌功能团。对绿盲蜷必须采取农业防治和生物防治相结合的方法，辅以化学防治。更多还原

【Abstract】 A systematic survey was made in transgenic Bt cotton fields(with the IPM and the Chemical control cotton field of transgenic Bt cotton), routine cotton field and surrounding habitat (non-crop habitat) of cotton fields in Nanpi county, Hebei province, from 2001 to 2002.And arthropod biodiversity of different cotton fields, resistance of Bt cotton, and dynamics of arthropods population of surrounding habitat were studied in lab. The main results showed as follows:1. 147 species of arthropods in 69 families of 17 order were found in cotton fields. Among them, 61species in 32 families belonged to pests; 17 species in 10 families belonged to neutral arthropods; 69 species in 34 families belonged to natural enemies. The natural enemies included 6 species of ladybirds, 26 species of spiders in 11 families, 5 species predatory bugs in 5 families, 3 species of green lacewings, 18 species of parasitoids wasp in 9 families and 11 species of other natural enemies of 7 families.2. Analysis showed that there was no significant difference between transgenic Bt cotton fields and routine cotton field in diversity, dominance, evenness and abundance of species, functional groups, sub-community and community. However, in the cotton field with the IPM, diversity and evenness were increased and dominance was decreased significantly. Abundance of pest sub-community was also decreased, while Abundance of neutral and natural enemies sub-community was increased remarkably. Population multiplying and community reestablishing of arthropod in cotton fields mainly happen in July. And at the same time , in the cotton fields with the IPM and decreasing farm insecticide, the control efficiency of natural enemies would be improved significantly, and which resistance of Bt cotton become weak was minimized.Tthe stability of cotton eco-system was increased.3.Servey indicated that there was much natural enemies in surrounding habitat (non-crop habitat) of the cotton fields, such as wheat fields, weeds, corn fields. They immigrated into cotton fields from the surrounding habitat, which played the role as a Species pool of natural enemies, from the last ten-day period of May to the beginning of June. They raised their proportion to pest and control role.Limited by habitat, a large number of natural enemies emigrated cotton fields late June. From early July to late August, with aphids in cotton fields multiplying rapidly, natural enemies moved in from other habitat, such as spring corn fields, weeds, jujube trees. And then population began to recovery and community began to reestablish. After middleAugust, predators kept a stable population dynamics since the number of Thrips tabaci Lindeman, Bemisia tabaci Gennadius, Empoasca biguttula Ishida induced while the number of Aphis gossypii Glover reduced.4. The study of resistance of transgenic Bt cotton showed that there was no signifycant effect on the number of cotton bollworm eggs. The number of the rest bollworm larvae of each generation of Bt cotton field was significantly lower than that of routine cotton fields. Damages on all organs of 2nd, 3rd and 4th generation cotton were less than the control fields and the difference was also significant, which showed that transgenic Bt cotton has marked efficiency on controlling bollworm. However, because of the varied efficiency of transgenic Bt cotton due to different time and organs, it was effective to 2nd generation bollworm. As to 3rd and 4th generation bollworm, it is necessary to use chemical control 3-4 times. Another practical way was to release Trichogramma chilonis which could not only reduced bollworm eggs and made up the loss caused by the weak resistance, but cut down using of farm insecticide and protected natural enemies.5. Survey showed that Lygus lucorum Mayer-Diirhas 3 generations a year. The first generation moved in cotton field where they completed the other two generations. At the last ten-day period of September they lay eggs that live through the winter on cotton, weeds, dead leaves and branches of trees ectl更多还原