Reports on the discovery and preliminary studies of the invasive species Thecodiplosis japonensis (Uchida & Inouye) in Huangdao area of Shandong province
Author of the article:JIAO Ji-Peng1** WU Hai-Wei2 REN Li-Li1 CHEN Ru-Min3 LUO You-Qing1***
Author's Workplace：1. Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University, Beijing 100083, China; 2. Shandong Academy of Forestry, Jinan 250014, China; 3. Huangdao District Forestry Bureau, Qingdao 266400, China
Key Words：Thecodiplosis japonensis, identification, morphological characteristics, damage features
Abstract： [Objectives] This study was to identify the pest attacking three pine species in Qingdao being Thecodiplosis japonensis，and to study its morphological characteristics，distribution and damage characteristics to provide references for its monitor, control and prevention. [Methods] The eggs, larvae, pupae and adults of T. japonensis on Pinus thunbergii and P. densiflora in Shandong province were observed, photographed and compared. The morphological characteristics of sternal “Y” shaped spatula of the mature larvae were observed. The head ultrastructure of the mature larvae was observed by scanning electron microscopy. The genomic DNA was extracted and amplified by the universal primers. The sequence of the mitochondrial cytochrome oxidase subunit I (COⅠ) was sequenced and compared with the sequence in the NCBI database. The number of attacked needles and larvae per gall of each collected branches were counted, the correlation between the damage rate of the needles and the number of larvae per gall was calculated. Observe mating and oviposition behavior, and record its life history continuously. [Results] The morphological characteristics of sternal “Y” shaped spatula of the mature larvae and wing veins of adults were consistent with the description of T. japonensis. Neighbor-Joining phylogenetic tree was built based on the COⅠgene sequences, and the result indicated that specimen from Qingdao were gathered in the same branch with T. japonensis from Japan, with the bootstrap value of 100%. It is clear that the alien invasive species T. japonensis has been colonized in Huangdao area of Shandong province. T. japonensis attack P. thunbergii, P. densiflora and P. tabulaeformis mainly. Galls were formed by larvae feeding at the base of the needle in the current-year shoots. Infested needles stopped growing and becoming shorter than normal, and then withered and died gradually. [Conclusion] We proved that the pest damaging three pines in Huangdao district was T. japonensis, and described its biological characteristics in details. These results could provide references for the rapid identification of T. japonensis, and would provide the theoretical basis and reference for early monitoring.