| In recent years,with the deepening of mangrove scientific research,the damage of scale insects in mangroves has attracted more and more attention.However,most of the related studies are limited to small scope reports,and there is still a lack of systematic research on the damage of scale insects in mangroves in China.In this study,mangrove scale insect species,population genetic diversity of Lepidosaphes tapleyi and biological control were systematically analyzed in Fujian,Guangxi,Guangdong and Hainan,the most widely distributed mangrove in China.This study is to complete the species data of mangrove scale insect species and provide reference for follow-up control work of Lepidosaphes tapleyi.The main research results are as follows:(1)Eight species of scale insects in mangroves were reported for the first time.They were Lepidosaphes tapleyi,Aspidiotus nerii,Fiorinia sp.,Lepidosaphes beckii,Pinnaspis strachani,Coccoidae,and Pseudococcus cryptus,Coccus formicarii;A total of 14 species,13 genera and 3 families were found,of which 71.4%were the armored scale insects.Kandella obovata was the most susceptible to scale insects,and Hainan had the largest number of scale insects and the widest host range.There are five kinds of mangrove hosts for Lepidosaphes tapleyi.They are Kandelia obovate,Avicennia marina,Rhizophora stylosa,Excoecaria agallocha,Sonneratia apetala,respectively.(2)Based on the mitochondrial COI gene of Lepidosaphes tapleyi,20 haplotypes were found from different regions and different hosts,and Hap2 was the most frequent,accounting for 26.19%of all individuals.Hap5 was shared in Guangxi,Guangdong and Hainan,and Hap1 was shared in Guangdong and Guangxi.It was inferred that Hap5 was an ancestral haplotype based on the mediator network diagram.The degree of genetic differentiation among the total populations of Lepidosaphes tapleyi is high,but the degree of gene exchange is low.In the past relatively recent historical period,there was no obvious population expansion and continuous growth pattern,and the population size remained relatively stable.The degree of genetic differentiation among populations with different geographical distribution of the same host was great,and the degree of genetic differentiation among populations of different hosts in the same location depend on the level of gene communication.(3)The dominant natural enemy of Lepidosaphes tapleyi in Chinese mangroves is Aphytis chrysomphali(Mercet),and Encarsia elongate(Dozier)is also newly reported to parasitic Lepidosaphes tapleyi.In Haicang,Xiamen,the spawning and eclosion periods of Aphytis chrysomphali were concentrated in September,and it was mainly parasitic on the female adults of Lepidosaphes tapleyi.There was a lag effect in control of the pest.Aphytis chrysomphali could form a stable parasitism in a certain space,which was different from Lepidosaphes tapleyi population which was greatly affected by the tide level and tree height.The total parasitization rate of Lepidosaphes tapleyi female adults in Fujian and Guangxi was 3.1%-26.3%,which was higher in Guangdong and Hainan(21.7%-49.2%).Among them,the co-existence of Aphytis chrysomphali and Encarsia elongate significantly increased the parasitization rate of the population. |
