Department of Entomology, University of Wisconsin-Madison, 1630 Linden Dr., Madison, WI 53706, USA.
J Econ Entomol. 2010 Jun;103(3):718-25. doi: 10.1603/ec09377.
Trees in the genus Populus can provide substantial commercial and ecological benefits, including sustainable alternatives to traditional forestry. Realization of this potential requires intensive management, but damage by defoliating insects can severely limit productivity in such systems. Two approaches to limiting these losses include cultivation of poplar varieties with inherent resistance to pests and application of microbial pesticides. Little is known about the interaction between host resistance and the ability of poplars to support the efficacy of biocontrol agents. The research described here was conducted to survey the effect of hybrid poplar clones on gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), a pest on these trees. We assessed the effect of various poplar clones on larval performance and susceptibility to Bacillus thuringiensis subsp. kurstaki. Larvae were reared from hatching on the foliage of 25 hybrid poplar clones and we monitored larval survival, development time, and weight at fourth instar. Eight of these clones showed high resistance against gypsy moth. The remaining clones showed high variation in their effect on larval performance. We evaluated the susceptibility of third-instar larvae to B. thuringiensis subsp. kurstaki when reared on the 17 remaining clones. There was a significant effect of poplar clone on time to death after ingestion of B. thuringiensis subsp. kurstaki. The susceptibility of gypsy moth larvae to B. thuringiensis on various clones was not correlated with the effects of these clones on larval performance in the absence of B. thuringiensis, suggesting this interaction is more complex than merely reflecting higher mortality to previously stressed larvae.
杨属树种可为商业和生态带来巨大效益，包括为传统林业提供可持续替代品。要实现这一潜力需要进行集约化管理，但食叶昆虫的损害可能会严重限制此类系统的生产力。限制这些损失的两种方法包括培育具有内在抗虫性的杨树品种和应用微生物农药。人们对宿主抗性与杨树支持生物防治剂功效的能力之间的相互作用知之甚少。此处描述的研究旨在调查杂交杨树无性系对舞毒蛾（Lymantria dispar）（鳞翅目：毒蛾科）的影响，舞毒蛾是这些树木的害虫。我们评估了不同杨树无性系对幼虫性能和对苏云金芽孢杆菌亚种的敏感性的影响。幼虫从孵化开始就在 25 个杂交杨树无性系的叶片上饲养，并监测幼虫的存活率、发育时间和四龄幼虫的体重。其中 8 个无性系对舞毒蛾表现出高抗性。其余无性系对幼虫性能的影响差异很大。我们评估了第三龄幼虫在剩余 17 个无性系上饲养时对苏云金芽孢杆菌亚种的敏感性。幼虫摄入苏云金芽孢杆菌亚种后的死亡时间受杨树无性系的显著影响。在没有苏云金芽孢杆菌的情况下，舞毒蛾幼虫对各种无性系的敏感性与这些无性系对幼虫性能的影响无关，这表明这种相互作用比仅仅反映先前受压力的幼虫死亡率更高要复杂得多。
