| A survey of the plant parasitic nematodes on vegetables was carried out in Lanzhou, Honggu, Tianshui district of Gansu Province,North-west of China ,from March to August, 2002. More than 120 soil samples were collected around the rhizosphere of tomato, Pepper, eggplant, cucumber, broccoli, turnip, bean, celery. 25 species belonging to 15 genera were identificated, including Tylenchorhynchus clarus, T.mashhoodi, T.aerolatus; Merlinius brevidens, M.communium-, Pratylenchus neglectus, P.hexincisus, P.scribneri; Filenchus cylindricollis, F.vulgaris, F.ditissimus , Aphelenchus avenae , A.solani ? Helicotylenchus dihystera, H.tropitw, Psilenchus hilarulus-, Macroposthonia xenoplox-, Boleodorus simiiis-, Meloidogyne spp., Malenchus spp., Miculenchus spp., Aphelenchoides spp., Bursaphelenchus spp., Aphelenchoides spp. and Ditylenchus spp.. Among them, many genera and species have not been reported in Gansu Province so far. Several species, such as T.clarus, T.mashhoodi, T.aerolatus, M.brevidens, P.neglectus, P.hexincisus and P.scribneri are the most common nematodes species on vegetables in this study. M. brevidens was frequently recovered with relatively high population density around the rhizospher of eggplant and pepper in Diaochang of Arming district, Lanzhou, it had seasonal dynamics following the host nutrition etc.rDNA-ITS RFLP was used for identification and characterisation of fifteen population of Meloidogyne on broccoli, tomato from Shunyi of Beijing; lettuce, peanut, weed from Jianyang of Sichuan; banana from Manning of Guangxi; tobacco from Junan of Shandong; tobacco from Luoyang of Henan; tomato, enterolobius, pepper, guava from Danzhou of Hainan; graudiflorum from Anhui; tomato from Belgium. The ITS regions were amplified using F195 and V5367 primers and yielded a single fragment of about 770bp for all samples. No PCR products were obtained in the negetive control. A total 10 scored fragments were obtained with 3 restriction enzymes digestion. Intraspecific polymorphism was revealed by Haelll Dral and AM digestion. The Haelll digested ITS products of M.incognita and M.javanica ,yielded three fragments having lengths approximately 370bp 220bp 180bp; The Dral digestion yielded three fragments having lengths approximately 400bp 240bp 130bp and the AM digestion yielded two fragments having lengths approximately 420bp 180bp. At the same time, additional bands were also obtained, the sizes of them were about 770bp 520bp and 770bp 600bp by Haelll and Dral degistion, respectively. This showed heterogenecity existed in the ITS regions ofM. incognita and M.javanica from China. Haelll did not digest ITS product of M.enterolobii , one brand about 400bp was obtained by the Dral digestion and three fragments having lengths approximately 600bp 420bp 180bp were obtained by the Alul digestion. The results showed that none of three enzymes differentiated M. incognita and M.javanica from each other.Soil fumigation with Metham sodium gave better effects to root-knot nematodes disease on tomato. 35% Metham sodium ,which was produced by Liming Chemical-industry Ltd. Jiangsu province. When application dosage were 2kg/mu 4kg/mu 6kg/mu, it decreased population of second-stage juveniles of Meloidogyne incognita up to 80.76% 88.10% 91.57%, compard with untreatment, respectively, it increased tomato yield 5.99% 7.29% 7.46%, respectively. Comparing nematicide-35% Metham sodium, which was produced by Agrichemical Ltd. Shenyang, When application dosage was 4kg/mu, its Controlling effect to second-stage juveniles of M.incognita on tomato was 80.30%, compared with untreatment, it increased tomato yield 5.66%. The experiment results showed that 35% Metham sodium was a effective soil fumigation for controlling root-knot nematodes.
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