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。
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Their first map focuses on Africa, where worm infestations are worst.
他们的第一批地图着手于非洲，因为那里是寄生虫感染最多的地方。
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Rothamsted Research, home to the Broadbalk experiment, has been tracking aphid infestations for 50 years.