The southeastern United States has been experiencing unexplained sugarberry (Celtis laevigata) mortality for over a decade, representing one of the most severe and widespread Celtis mortality episodes ever reported from North America. Here we describe external symptoms, progression of mortality, and the known geographic extent of the problem. More than half of all trees monitored at one site within the affected area died over five years of observation. Although many trees died within a year of first exhibiting symptoms (e.g., small yellow leaves, branch dieback, premature leaf fall), many others continued living for years after becoming symptomatic. A preliminary insecticide trial found no improvements in survivorship among trees treated with insecticides, emamectin benzoate and imidacloprid, relative to control trees. Our findings suggest the problem will likely continue and become more widespread in the coming years.

中文翻译：

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美国东南部 Sugarberry (Celtis laevigata) 枯萎和死亡率的进展

十多年来，美国东南部一直在经历无法解释的甘莓 (Celtis laevigata) 死亡事件，这是北美报告的最严重和最广泛的 Celtis 死亡事件之一。在这里，我们描述了外部症状、死亡率的进展以及问题的已知地理范围。在受影响区域内的一个地点监测的所有树木中，超过一半的树木在观察五年后死亡。尽管许多树木在首次出现症状后一年内死亡（例如，小黄叶、树枝枯死、过早落叶），但许多其他树木在出现症状后仍能存活数年。一项初步的杀虫剂试验发现，相对于对照树木，用杀虫剂、甲维菌素苯甲酸酯和吡虫啉处理的树木的存活率没有提高。