Investigation And Identification Of Plant-parasitic Nematodes On Landscape And Ornamental Plants In Guangdong

A survey of plant-parasitic nematodes on landscape plants was carried out in Guangzhou City,Foshan City,Huizhou City,Zhuhai Ctiy,Yingde City and Dongguan City of Guangdong Province from July 2016 to February 2018,Totaly 596 samples were collected.Of these,plant-parasitc nematodes were isolated from 533 samples.Main results are as follows:1.By using morphology combining with molecular techniques,22 species and 26 genera of plant-parasitic nematodes.According to the frequency of occurrence,the top ten nematode genera are: Helicotylenchus,Filenchus,Aphelenchoides,Meloidogyne,Rotylenchulus,Tylenchorhynchus,Pratylenchus,Hemicriconemoides,Ditylenchus and Xiphinema.2.Scutellonema guangdongensis sp.n.is a formulated new species.It can be differed from all other Scutellonema spp.by morphological and molecular characteristics.It is characterized by a lip region bearing three annulis,In frontal view 15-18 longitudinal striations visible on the basal ring of lip region.Stylet well developed,and knobs rounded.Lareral field is areolated at level of scutellum and also in anterior part of body up to posterior glandular part of esophagus.Epiptygma usually inconspicuous,folded in the vuval.Scutella situated at level of anus.Tail terminally rounded;number of cuticular rings on ventral side varies from 6 to 8.The most closely related species are S.banglorensis and S.unum.S.guangdongensis sp.n.differs from S.banglorensis by the basal ring of lip region,number of cuticular rings on ventral side and the folded Epiptygma.The new species from S.unum by less number of rings at lip region,shorter Stylet,visible spermatheca without sperm and rectum without overlapping by intestine.In addition,Phylogenetic trees inferred from BI analysis based on LSU D2D3,LSU ITS and mtDNA COⅠ revealed that S.guangdongensis sp.n.can be distinguished from all describled Scutellonema spp.3.F.cabi,H.cuspicaudatu and M.palustre are new record species in China;P.aculentus is new record species in China Mainland;In the 22 species,there are 11 new host record,they are Ficus microcarpa,Duranta repens,Syngonium podophyllum,Ervatamia divaricata,Tradescantia zebrine,Bambusa chungii,Alocasia macrorrhiza,Roystonea regia,Boehmeria nivea,Loropetalum chinense and Jatropha pandurifoliaThe species,distribution and identification of the plant-parasitic nematodes on landscape plants were investigated in Guangdong,which established foundation for further study on the damage of the plant-parasitic nematodes.On the other hand,it will be helpful as scientific basis for the disease control and quarantine of plant-parasitic nematodes in Guangdong.It was also significant to protect the production and trade of landscape and ornamental plants as well as ecological security in this region.