A root-knot nematode (RKN) parasitizing rice (Oryza sativa L.) and causing damage in Santa Catarina (SC), Rio Grande do Sul (RS) and Paraná (PR) states (Brazil) was identified as Meloidogyne ottersoni (Thorne 1969) Franklin 1971. The species is redescribed from the Brazilian population from Meleiro (SC) and compared with the description of M. ottersoni from Wind Lake (Wisconsin, USA) with additional morphological, biochemical and molecular characterization. The female and male bear smaller stylets: 10-12 μm, 14-16 μm, respectively, when compared with M. graminicola: 12-14 μm, 16-18 μm, and M. oryzae: 14-16 μm, 18-20 μm. Meloidogyne ottersoni presents perineal patterns located on the contour of a slight protuberance. Striae are mostly continuous, never raised by transverse irregular striae, as frequently observed in M. graminicola and M. oryzae. Meloidogyne ottersoni belongs to the RKN group 11 described by Jepson (1987); the reproduction is by meiotic parthenogenesis and the somatic chromosome number is 18. The tail of second-stage juveniles is very long and thin, and tapers to a long, narrow, irregular hyaline terminus (M. ottersoni, 20.5 μm vs M. graminicola, 17.9 μm and M. oryzae, 22.0 μm, respectively). The ability of the Brazilian M. ottersoni population to parasitize canary grass, Phalaris arundinacea L. (type host), and barnyard grass, Echinocloa crus-galli, was confirmed. Biochemically, the esterase profile of M. ottersoni lacks any band (Est Ot0, Rm=0), which differentiates it from M. graminicola and M. oryzae (Est VS1, Rm=0.70 and Est O1, Rm=1.02, respectively). In Maximum Likelihood analysis of ITS, D2D3 and COXII-16S rRNA sequences, populations of M. ottersoni from different states of Brazil clustered together and were separated from other Meloidogyne spp., thus confirming that all four populations are very similar and conspecific.

根结线虫（RKN）寄生于稻米（Oryza sativa L.）中，并在圣卡塔琳娜州（SC），南里奥格兰德州（RS）和巴拉那州（PR）（巴西）造成破坏，被确定为Meloidogyne ottersoni（Thorne 1969） ）富兰克林（Franklin），1971年。该物种从Meleiro（SC）的巴西种群中重新描述，并与Wind Lake（美国威斯康星州，美国）的M. ottersoni进行了描述，并进行了额外的形态，生化和分子表征。雌性和雄性较小的探针：分别比粉虱分枝杆菌：12-14μm，16-18μm和米曲霉：14-16μm，18-20分别为10-12μm，14-16μm微米 根结线虫呈现会阴模式，位于略微隆起的轮廓上。皮纹大多是连续的，不会被横向不规则条纹升高，如在经常观察到M.蛛和稻瘟病菌。Meloidogyne ottersoni属于Jepson（1987）描述的RKN组11；繁殖是通过减数分裂孤雌生殖而产生的，体细胞染色体数为18。第二阶段幼虫的尾巴很长很细，逐渐变细成一个长而狭窄的不规则的透明末端（M. ottersoni，20.5μmvs . graminicola， 17.9微米和稻瘟病菌，22.0微米，分别地）。巴西ottersoni种群寄生金丝雀草的能力，虉L.（类型主机）和稗草，稗稗，得到了证实。生化方面，ottersoni的酯酶谱缺少任何条带（Est Ot0，Rm = 0），这使其区别于graminicola和M. oryzae（Est VS1，Rm = 0.70和Est O1 ， Rm = 1.02）。在ITS，D2D3和COXII-16S rRNA序列的最大似然分析中，来自巴西不同州的ottersoni种群聚集在一起，并与其他Meloidogyne spp。分开，从而证实了这四个种群非常相似且具特异性。