Sweet Potato Nematode Diseases And Identification Of Nematode Species

This paper studied the systematic status of sweet potato stem nematode in China. The specimens of sweet potato nematode were collected from 11 areas of Hebei, Shangdong, Anhui provinces. China. Sweet potato nematode species were identified as Ditylenclus destructor through observing their characteristics by light microscope and scan electron microscope and amplificating rDNA-ITS1 region by PCR and analyzing sequence and mensurating their hosts. The characteristics were showed by scanning electron microscope: Labial field with four annules; Lateral field with six incisures and areolated. But the first description of Ditylenchus destructor was without labial annules and areolated. The result of the ITS 1 DNA sequencing revealed that sweet potato stem nematode losed 188bp in ITSl compared with D. destructor of foreign. Sweet potato stem nematode were inoculated on sweet potato and potato, the result show that potato was not the optimum host of sweet potato stem nematode. And this result reflected that the difference of Pathogensis between sweet potato stem nematode and D. destructor.Inotulating tests approved that sweet potato stem nematode could infect peanut in China for the first time, and it could caused composite infection on sweet potato with Fusarium solani or F. oxysporum.Fifteen species of plant parasitic nematode were identified from diseased tubers, roots and rhizosphere soil of sweet potato, among these two were new species: Ditylenchus destructor, Pratylenchoides batatae n.sp., Megadorus batatae n.sp, Meloidogyne incognita, Rotylenchulus reniformis, Pratylenchus coffeae, Aphelenchoides bicaudatus, Aphlenchoides composticola, Aphelenchus avenae, Rhabdotylenchus guangdongensis, Filenchus sp., Tylenchorhynchus unnulatus. Helicotylenchus dihystera, Ditylenchus myceliophagus.Sweet potato reniformis nematode disease was recorded firstly in China. We found Rotylenchulus reniformis together with Meloidogyne incognita occurred in the same field of sweet potato. Aphelenchoides bicaudatus and Phomopsis batatae were recorded to compositedly cause a new disease: sweet potato dry crack rot disease.