【目的】探明美国白蛾（Hyphantria cunea）成虫在南京地区的发生规律和种群分布，为美国白蛾的科学防控提供参考。【方法】2019—2022年，在每年的4月1日—9月15日采用性信息素诱集法监测美国白蛾成虫，记录各监测点位成虫数量，分析南京地区美国白蛾成虫的发生情况。通过地统计学方法研究2019—2022年美国白蛾在南京地区的空间分布型，使用GS+ 9.0软件中的Autocorrelation工具计算半方差函数模型参数。按照3~5、6~10、11~20、21~30、31~50、51~70、71~100和100只以上等标准对美国白蛾监测点位进行分类，利用ArcGIS软件绘图分析美国白蛾种群分布。统计美国白蛾各世代始见期、始盛期、高峰期、盛末期和结束期，使用STDEV函数计算美国白蛾成虫理论期距值。【结果】2019—2021年美国白蛾成虫诱集量呈逐年上升趋势，2022年较往年呈下降趋势。美国白蛾在南京地区1年发生3代，越冬代成虫数量最大（有2个羽化高峰），第1代数量次之，第2代数量最少。美国白蛾在全市大部分区域均有分布，空间上呈聚集分布，中心城区、交通道路沿线、景区附近、水域周边等是美国白蛾高适生区。越冬代始见期至第2代结束期平均期距值分别为12.75、7.00、8.50、7.75、28.75、11.25、6.00、6.25、11.75、17.00、5.00、4.75、7.00、14.25 d。【结论】美国白蛾在南京地区每年发生3代，随着发生期不断提前，美国白蛾年4代化的可能性不断增强。美国白蛾在空间上呈聚集分布，中心城区、交通道路沿线、景区附近、水域周边等是美国白蛾高适生区。

【Objective】This study aims to elucidate the occurrence regularity and spatial population distribution of adult Hyphantria cunea in Nanjing，in order to provide a scientific basis for its prevention and control.【Method】From 2019 to 2022，adult H. cunea were monitored annually using sex pheromone traps between April 1st and September 15th each year. The number of adults captured at each monitoring site was recorded to analyze interannual occurrence trends. The geostatistical method was applied to characterize the spatial distribution patterns of H. cunea across the study area. Semivariogram model parameters were calculated with the Autocorrelation tool in GS+ 9.0 software. Based on trap counts，monitoring sites were classified into eight density grades： 3-5，6-10，11-20，21-30，31-50，51-70，71-100，and >100 adults. Spatial distribution maps were generated using ArcGIS software. For each generation，the initial emergence，peak-start，peak，peak-end，and termination periods were determined. The STDEV function was used to compute theoretical interval values between the occurrence phases of adult H. cunea.【Result】From 2019 to 2021，adult catches showed a year-on-year increasing trend，followed by a decline in 2022. In Nanjing，H. cunea completes three generations per year. The overwintering generation exhibited the highest population abundance，with two developmental peaks，followed by the first generation； the second generation had the smallest population size. Adults of H. cunea were widely distributed across most parts of Nanjing，displaying an aggregated spatial distribution pattern. High-suitability areas for H. cunea included central urban zones，regions along major transportation corridors，areas adjacent to scenic spots，and neighborhoods surrounding water bodies. The average interval values between successive occurrence phases—from the initial emergence of the overwintering generation to the termination of the second generation—were 12.75，7.00，8.50，7.75，28.75，11.25，6.00，6.25，11.75，17.00，5.00，4.75，7.00 and 14.25 days，respectively.【Conclusion】H. cunea in Nanjing reproduces three generations annually. However，as the occurrence periods continue to advance，the potential for the emergence of a partial fourth generation is increasing. The spatial distribution of H. cunea is clustered，with high-suitability areas concentrated in central urban districts，transportation corridors，scenic spots，and riparian zones.