寄生小蜂对小青×黑杨树皮及杨圆蚧挥发油的行为反应

Four-armed airflow olfactometer was used to determining the foraging behavior ofPteroptrix longgiclava (Girault) (Hymenoptera: Aphelinidae) andEncarsia gigas (Tshumakova) (Hymenoptera: Aphelinidae) to the essential oils which emitted from the healthy bark ofPopulus pseudo-simonii×P. nigra, the infested bark injured byQuadraspidiotus gigas (Thiem & Gerneck), the body and scale of fixed 1st-instar-nymph ofQ. gigas. The results from these experiments showed that the volatile oils produced from the injured bark and from the scale of fixed 1st-instar-nymph had a higher attractive ability to female adults of the two species of wasps. The essential oil produced from the scale of the pest at dosages of 3–7 μL and the essential oil emitted by injured bark at dosages of 5–9 μL had a stronger alluring effect on the host searching behavior ofPteroptrix longgiclava. The essential oil from the body of fixed 1st-instar-nymph ofQ. gigas also had certain effect on the host locating effort ofPteroptrix longgiclava andEncarsia gigas. Those two wasps did not shown any reaction to the essential oil produced by the healthy bark of poplar. Foundation item: This paper was supported by National Natural Science Foundation of China (39970620) and the “TRAPOYT” Biography: CHI De-fu (1962-), male, Ph.D., Professor in Northeast Forestry University, Harbin 150040, P.R. China Responsible editor: Chai Ruihai     

小蜂对杨圆蚧的趋性及杨圆蚧挥发物分析

采用四臂式嗅觉仪测定了长棒四节蚜小蜂和黄胸扑虱蚜小蜂对杨圆蚧1龄固定若虫的虫体、介壳、虫体与介壳复合体的趋性。结果表明，介壳和虫体与介壳复合体对两种小蜂具有较强的吸引力。两种小蜂对气味源的剂量都比较敏感。采用敢相色谱－质谱联机分析方法，分析了杨圆蚧1龄固定若虫虫体及介壳所释放的挥发性物质的成分和各组分所占比例，分析表明，虫体和介壳中释放出的挥发性物质均含有9个组分，但这9个组分在虫体和介壳挥发物中的比例略有变异。     

杨盾蚧天敌种类及主要天敌自然控制效果调查

对克拉玛依农田开发区防护林上发生的杨盾蚧天敌昆虫种类及其自然控制作用进行了调查。调查发现,杨盾蚧天敌昆虫主要是长棒四节蚜小蜂和孪斑唇瓢虫,其中长棒四节蚜小蜂自然寄生率高达41.5%。此外,在室内对杨盾蚧的主要捕食性天敌孪斑唇瓢虫的捕食量以及孪斑唇瓢虫和杨盾蚧之间的密度功能反应进行了研究。研究发现,孪斑唇瓢虫对杨盾蚧若虫具有较大的捕食潜能,而且对若虫的寻找效应均随着猎物密度的增加而降低。     

杨圆蚧利它信息素和小蜂阻止产卵信息素对小蜂控制力的影响

寄主对寄生性天敌具有引诱作用和寄生小蜂分泌产卵信息素．是保证小蜂对寄主有较高的控制力的必要条件，研究发现杨圆蚧中存在着有利于长棒四节蚜小蜂和黄胸扑虱蚜小蜂寻找寄主和产卵的一类化学物质——利它信息素．主要存在于杨田蚧的介壳中．是一类具有水溶性特征的化台物．可帮助长棒四节蚜小蜂和黄胸扑虱蚜小蜂进行寄主的定位和辨识。因此可以保证在寄主低密度条件下．成功地进行寄主定位．对寄主进行有效的控制。长棒四节蚜小蜂和黄胸扑虱蚜小蜂在寄主杨圆蚧一龄固定若虫体上产卵后．留下可以阻止同种的其它个体或异种的个体进行寄主检查和产卵的物质．即产卵标速信息素。这样便极大地减少了杨田蚧之间复寄生现采的发生．确保了杨圆蚧若虫体内的小蜂有充足的营养．也使小蜂利用有限的卵．控制尽可能多的寄主．使杨圃蚧和小蜂保持在一定的种群水平。     

营林措施及天敌对杨盾蚧的控制效果评价

从森林健康理念出发,以克拉玛依市农业开发区的农田防护林为研究对象,对防护林采取修枝、间伐、截干等营林措施调控林分的密度、改善林分健康水平,从而达到控制杨盾蚧虫口密度的目的.与此同时,对杨盾蚧主要天敌种类及其控制效果进行了评价.结果表明,营林措施对各处理区林分生长有一定的促进作用,修枝区、修枝间伐区和截干区的平均虫口减退...