The Relationship Between The Occurrence Of Pratylenchus And Other Nematodes And Weed Diversity Of Sweet Potato Fileds In Huaibei Area

Sweet potato(Ipomoea batatas)is an important food and cash crop in Huaibei area,and nematode disease has always been a major threat to it.Up to now,most studies and reports on the nematodes diseases of sweet potato have focused on Ditylenchus detructor,and there have been few reports on the Pratylenchus on sweet potato.However,unlike the Ditylenchus detructor,which is often localized.The Pratylenchus nematode is widely distributed,host range wide,and spreads rapidly.Once a large area infection occurs,it will pose a great threat to agriculture and forestry production.Investigate the main pathogenic nematodes of sweet potato in Huaibei area,for analyzing the occurrence trend of them to provide a element of theory for the sweet potato nematode diseases management.Investigated species of weeds and collected sweet potato with its rhizosphere soil samples in Yuzhuang,Hewan Huanglin,Tianqiao,Wada,Laoji,Yangqiao,Shanqiao,Yang Xiaojie,Tongcheng,Pangying Township,Guanmiao Town,Linquan,and Sanjie,Shuxiang of Mingguang,which are the representative sweet potato planted regions of Anhui Province.The survey founds that Setaria viridis,Digitaria sanguinalis and other 88 species of weeds,including 11 species of vicious weeds in sweet potato fileds.The soil nematodes were detached by shallow tray and identified using light microscopy.Nematode morphological data were calculated by De Man formula.According to the morphological characteristics of nematodes,parasite nematodes such as Pratylenchus and Aphelenchoides were identified.The most risky families are Pratylenchus,Helicotylenchus,and Ditylenchus,and it is necessary to strengthen monitoring in this area.The Pratylenchus were further identified to Pratylenchus penetrans,Pratylenchus thornei,Pratylenchus loosi,Pratylenchus neglectus,and Pratylenchus zeae,Pratylenchus brachyurus,Pratylenchus mediterraneus,and Pratylenchus coffeae;among them,P.zeae and P.neglectus,P.loosi,and P.mediterraneus are recorded for the first time in Anhui Province,and P.mediterraneus the is first record in China.Survey has not found D.detructor in all areas of Linquan.Applying the data of 9 samples from Linquan County,such as Huangling Town,the frequency of Pratylenchus was calculated,the diversity indexes of plant species and soil nematode communities was determined,by using Excel and DPS software.Evaluate the relationship between plant diversity indexes and soil nematode communities,and analyze the correlation coefficient.It was found for the first time that the frequency of Pratylenchus on sweet potato was significantly negatively correlated with Shannon’s index of weeds diversity(r=-0.53,p<0.1),and was positively correlated with the Shannon’s index of soil nematode communities(r= 0.74,p< 0.05).The frequency of parasitic nematode was positively correlated with the Shannon’s index of weeds diversity(r= 0.32,p<0.01).The Frequency of Rhabditida was significantly positively correlated with the weed diversity Shannon’s index(r= 0.67,p<0.05).In summary,the analysis shows that the stability of the ecological chain of nematodes was conducive to the occurrence of Pratylenchus;the diversity of weeds was conducive to the stability of soil nematodes.In this regard,we advocate proper weed control to maintain farmland ecosystem stability and control nematode disease injury level below the economic threshold.