Population dynamics,spatial distribution pattern,mating and spawning behavior of Fenghuang Dancong tea tree longhorn beetle in Chaozhou

【Objective】To evaluate the occurrence regularity,mating and spawning behavior of Fenghuang Dancong tea tree Trachylophus sinensis(Gahan) in Chaozhou,so as to provide the scientific basis for prediction and control of longhorn beetle of Fenghuang Dancong tea tree in Chaozhou.【Method】The population dynamics of longhorn beetle larvae in Dancong tea area of Chaozhou was investigated by the fresh faeces at tea tree cavities in the field,and the spatial distribution of longhorn beetle larvae was calculated by population aggregation index method and the population dynamics of adult longhorn beetles were investigated by using sex pheromone trapping. The mating and oviposition behaviors of adult longhorn beetles were studied by indoor observation.【Result】The results of larvae population dynamics monitoring showed that longhorn beetles occurred in the three sample plots and the fastigium of population quantity was from August to November. The infestation rates of ancient tea garden in Da' an Village sample plot was higher than that of the new tea garden in Da' an Village and new tea garden in Shanwaishan Village. Two obvious fastigiums of infestation rates of longhorn beetles(from mid-August to mid-September and from mid-October to mid-November,2020) were observed and the infestation rates of the two fastigiums were 12.7% and 12.6%,respectively. The infestation rates showed a trend of increase with higher altitude. The infestation rates of new tea garden in Da' an Village(1100 m) and new tea garden in Shanwaishan Village(1200 m) in September were 9.3% and 8.1%,respectively,with no significant difference(P>0.05) appeared. The results of aggregation indices showed that the longhorn beetle larvae was clustered in various sample plots. The results of adult population dynamics monitoring showed that the tea adult longhorn beetles was T. sinensis(Gahan) in the ancient tea garden of Da' an Village. The emergence period of longhorn beetles starts from mid-May to late-May and the number of entrapment gradually increased. An obvious fastigium of population quantity of longhorn beetles was witnessed from mid-July to late-July,with the amount of a single trap number of(11.67±2.62) and the male-female ratio of 1:1.92. The emergence period ended from late July to early August,and the number of traps decreased gradually. The results of oviposition of T. sinensis showed that male and female adults could mate multiple times,with false mating common among males. Females tended to lay eggs on branches,which is 5.42 times more than that on tea leaves. Females could lay eggs repeatedly,and the largest number of eggs was(9.00±5.10) per female on the 5th day after mating,with fewer eggs being laid each time subsequently.【Conclusion】The fastigium of longicorn beetle larvae in Dancong tea tree garden is from August to November during which longhorn beetle larvae clustered in the field and a positive correlation is found between the infestation rates and altitude. A fastigium of T. sinensis population quantity is from mid-July to late July and the male and female T. sinensis adult could mate multiple times,with female adults lays eggs on branches. The occurrence regularity of Dancong tea tree longhorn beetles in Chaozhou provides reference for effective physical,agricultural,biological and chemical control before the fastigium,so as to reduce the population base and achieve better control effect.