Further research has shown that caterpillars become virtually immune to the wilt virus as the trees on which they feed respond to increasing defoliation.
进一步的研究表明，毛虫对萎蔫病毒几乎具有免疫力，因为它们赖以为生的树木会对越来越多的落叶做出反应。
2
The defoliation of millions of acres of trees by massive infestations of gypsy moth caterpillars is a recurring phenomenon in the northeastern United States.
在美国东北部，舞毒蛾毛虫的大规模侵扰导致数百万英亩的树木落叶，这是一个反复出现的现象。
3
Short-term effects include the disturbances directly associated with the action of the pest, which may cause the defoliation, loss of vigor, or death of trees.