The Species Identification Of Cerambycid Beetles And Nematodes Carried By Them In Forest Stand Invaded By Pine Wood Nematode In Some Parts Of China

Pine wood nematode(Bursaphelenchus xylophilus)was discovered in 1982 in China and spread to southern China in 20 years.In this places,pine wood nematode’s vector beetle is Monochamus alternatus.In 2016,pine wilt disease broke out in Liaoning Province.According to the investigation,Monochamus saltuarius is a new vector beetle of pine wood nematode,and Pinus koraiensis,Larix kaempferi,Larix olgensis,Larix gmelinii var.principis-rupprechtii and Pinus sylvestris var.mongolica are new host tree species of pine wood nematode.In order to identify the species of vector beetles in Fushun,Liaoning Province,this study investigated the species of cerambycid beetles in stand invaded by pine wood nematode by trap monitoring.In order to identify the species of nematodes carried by dominant cerambycid beetles in pine forests in Fushun,Liaoning Province,nematodes of the captured long horn beetles were isolated,cultured and identified.In addition,we also investigated the species of cerambycid beetles in pine forests in other parts of China.The main results are as follows:(1)The species of cerambycid beetles in stand invaded by pine wood nematode were identified in Cangshi Village,Fushun,Liaoning Province.From 2019 to 2020,in Fushun,Liaoning Province,we carried out a trapping experiment in mature forests of P.tabulaeformis,Pinus koraiensis,L.gmelinii var.principis-rupprechtii.A total of 13,307 cerambycid beetles of 34 species were trapped.The results show that a mixture of eight pheromone components with host volatiles and F8 attractant that are hung on a same trap showed good attractant effect and captured the most species and number of cerambycid beetles.7 species among them harm conifers of all the captured longicorn,including M.saltuarius(dominant specie),Acanthocinus griseus,Acanthocinus aedilis,Arhopalus rusticus,Asemum striatum and Prionus insularis.According to their feeding and egg-laying habits,A.griseus and A.aedilis may transmit pine wood nematodes to healthy pine trees when they feed,while A.rusticus,A.striatum and P.insularis don’t supply nutrition and lay eggs without wounds,so it’s less possibility that they effectively transmit pine wood nematode.(2)The species of nematodes carried by dominant cerambycid beetles were identified in pine forests in Fushun,Liaoning Province.From 2019 to 2020,the nematode isolation and culture of cerambycid beetles in Fushun,Liaoning Province showed that M.saltuarius carried pine wood nematode before July 2019,and the rest of time and the rest dominant cerambycid beetles did not carry pine wood nematode.In addition,M.alternatus could carry Deladenus sp.,A.rusticus could carry five kinds of nematodes: related specie of Anguina tritici,Deladenus sp.,Steinernema sp.,related specie of Pratylenchus brachyurus,Cephalenchus sp.,and Acanthocinus griseus could carry Contortylenchus sp..(3)The species of cerambycid beetles in pine forests in other parts of China were identified.A mixture of eight pheromone components with the two host volatiles was placed in pine forests of 11 other Chinese sites,including Saihan dam,Hebei Province,Mulan paddock,Hebei Province,Jiufeng,Beijing,Hangzhou,Zhejiang Province,Heilihe Nature Reserve,Inner Mongolia Autonomous Region,Jiagedaqi,Inner Mongolia Autonomous Region,Dexing,Jiangxi Province,Quannan,Jiangxi Province,Changsha,Hunan Province,Weihai,Shandong Province,and Nanjing,Jiangsu Province.Overall,790 cerambycid beetles of 29 species were trapped,and 14 species among them harm conifers,including 2vector beetles of pine wood nematode had been reported in China: M.alternatus,M.saltuarius,and 3longhorn beetles that could become vector beetles of pine wood nematode in future: Monochamus sutor,Monochamus urussovi and Monochamus galloprovincialis.The result showed that there were almost Monochamus spp.in the forest from south to north,and most of them were dominant species in most study sites,with a large number and a high proportion,indicating that pine wood nematode has an extremely broad potential transmission area.Based on others’ studies,this study believes that M.saltuarius is the vector beetle of pine wood nematode in Cangshi Village,Fushun,Liaoning Province,and it is necessary to strengthen prevention and control measures to avoid the further spread of the pine wood disease.In addition,A.rusticus,A.striatum and A.rusticus may transmit pine wood nematode,but this view needs more research to verify.The trapping results of pine wood nematode invaded forests in Fushun,Liaoning Province showed that a mixture of eight pheromone components with the two host volatiles and F8 attractant that were hung on a same trap had a better attracting effect on M.saltuarius.In other parts of China,we have captured M.sutor,M.urussovi and M.galloprovincialis.According to foreign reports,we speculate that they may be new vector beetles of pine wood nematode in northern China,and we need to pay enough attention to them.