【摘要】 小圆胸小蠹Euwallacea fornicatus是一种国际性重大林木害虫，也是近年国内外危害严重的重大蛀干害虫之一。2025年，在云南省普洱市澜沧拉祜族自治县古茶树害虫调查时发现该虫为害古茶树枝干。经调查，该虫在古茶树上呈现聚集分布特征，主要为害古茶树中上部枝干，且集中在某一枝干发生，单位面积蛀孔数达0.15个/cm~2。经对受害枝干室内饲养观察，收集羽化成虫进行形态鉴定和分子鉴定，确定为小圆胸小蠹。该小蠹虫幼虫在茶树枝干内钻蛀为害至化蛹，仅成虫阶段从受害枝干内部钻出，寻找新的钻蛀点，蛀孔和羽化孔周围残留有木屑及虫粪。雌雄成虫具有明显的性二型特征，新羽化的雌雄成虫均为黄褐色，而成熟的雌成虫为黑褐色、雄成虫为红褐色。此外，雌成虫体型显著大于雄成虫，表现在雌成虫体长、体宽、前胸背板和鞘翅长宽均显著高于雄成虫。成虫前胸背板呈半球形隆起，鞘翅后斜面平缓，刻点规则并具稀疏短毛，可据此与近缘种坡面方胸小蠹E.interjectus和阔面方胸小蠹E.validus区分。综上，本研究首次明确了为害云南古茶树的蛀干害虫为小圆胸小蠹，研究结果将为该虫的诊断识别、鉴定及其监测和防治提供依据。更多还原

【Abstract】 Euwallacea fornicatus is a globally important forestry pest and one of the major wood-boring insects causing severe outbreaks in recent years. In 2025, during an investigation of pests affecting old tea plants in Lancang Lahu autonomous county, Pu’er city, Yunnan province, this insect was found infesting the branches and trunks of old tea plants. Field investigations showed that the pest exhibited an aggregated distribution on old tea plants, mainly damaging the middle and upper branches and often concentrating on a single branch. The density of boreholes reached 0.15 holes/cm~2. Infested branches were collected and reared indoors, and the emerged adults were subjected to morphological and molecular identification, confirming the species as E.fornicatus. The larvae tunnel and feed within the branches of tea plants until pupation, and only adults emerge from the branches to search for new boring sites. Sawdust and frass were observed around both boring holes and emergence holes. Adult males and females showed obvious sexual dimorphism. Newly emerged adults of both sexes were yellowish-brown, while mature females were dark brown and males were reddish-brown. Additionally, female adults were significantly larger than males, with significantly greater body length, body width, pronotum and elytra length and width. The adult is characterized by a hemispherically convex pronotum and a gently sloping elytral declivity with regular punctation covered in sparse short setae. It can be readily distinguished from the closely related E.interjectus and E.validus by the above morphological features. In conclusion, this study confirmed for the first time that the wood-boring pest damaging old tea plants in Yunnan is E.fornicatus. These results provide a basis for the diagnosis, identification, monitoring, and control of this pest.更多还原