Machado A C Z, Dorigo O F, Mattei D
Instituto Agronômico do Paraná, 86047-902, Londrina, PR, Brazil.
Universidade Estadual de Maringá, 87507-190, Umuarama, PR, Brazil.
Plant Dis. 2013 Mar;97(3):431. doi: 10.1094/PDIS-09-12-0832-PDN.
Common bean (Phaseolus vulgaris F.) is one of the most important crops in Paraná State, which is responsible for almost 10% of the Brazilian production (4). Root knot nematodes, Meloidogyne spp., are common parasites of this crop worldwide, but damage caused by Meloidogyne inornata has not been reported. During a survey of nematode species present on common bean fields in Paraná State, Brazil, galled root samples of cultivars Tuiuiú and Eldorado were submitted, in June 2012, in the Nematology Laboratory from IAPAR, collected in the municipalities of Araucária (25°35'34″S, 49°24'36″W) and Santana do Itararé (23°45'18″S, 49°37'44″W). Plants did not exhibit any above-ground symptoms. The specimens were identified through perineal patterns and esterase phenotypes of 20 adult females extracted from dissected roots (2,3). The population densities observed in the samples were 140 and 700 J2 and eggs per gram of roots, respectively, for both samples. Characteristics were consistent with those described for M. inornata. For example, perineal patterns of M. inornata showed a high dorsal arch, with smooth to wavy striae, similar to those of M. incognita; but no punctate markings between anus and tail terminus were observed. However, from the esterase electrophoresis we obtained the I3 (Rm = 0.83, 1.15, and 1.32) phenotype, typical of M. inornata, a species-specific phenotype used to differentiate this species from M. incognita (1). Moreover, the excretory pore of adult females was located 32.1 (± 5.4) μm from the anterior end, consistent with the M. inornata description (25 to 53 μm) (1). To the best of our knowledge, this is the first report of M. inornata parasitizing common bean roots. This finding has great importance for Brazilian agriculture, since this nematode may damage common bean plants and become an additional problem for this crop. Additional work is necessary in order to elucidate the losses caused by M. inornata on common bean. References: (1) R. M. D. G. Carneiro et al. Nematology 10:123, 2008. (2) P. R. Esbenshade and A. C. Triantaphyllou J. Nematol. 22:10, 1990. (3) K. M. Hartman and J. N. Sasser. Page 115 in: An Advanced Treatise on Meloidogyne, Volume II Methodology. K. R. Barker et al., eds. Raleigh: North Carolina State University Graphics, 1985. (4) MAPA. Feijão, Ministério da Agricultura, Brasil. Retrieved from http://www.agricultura.gov.br/vegetal/culturas/feijao September 05, 2012.
普通菜豆（Phaseolus vulgaris L.）是巴拉那州最重要的作物之一，占巴西产量的近10%（4）。根结线虫（Meloidogyne spp.）是全球该作物常见的寄生虫，但尚未有关于南方根结线虫（Meloidogyne inornata）造成危害的报道。2012年6月，在巴西巴拉那州普通菜豆田线虫种类调查期间，将品种Tuiuiú和Eldorado的根结样本提交至巴拉那农业研究所线虫学实验室，样本采集于阿劳卡里亚市（南纬25°35′34″，西经49°24′36″）和伊塔拉雷桑塔纳市（南纬23°45′18″，西经49°37′44″）。植株未表现出任何地上部症状。通过从解剖的根中提取的20头雌成虫的会阴花纹和酯酶表型对标本进行鉴定（2,3）。两个样本中观察到的种群密度分别为每克根140条和700条二龄幼虫及卵。其特征与已描述的南方根结线虫一致。例如，南方根结线虫的会阴花纹呈高背弓，纹线平滑至波浪状，与爪哇根结线虫（Meloidogyne incognita）相似；但在肛门和尾端之间未观察到点状斑纹。然而，从酯酶电泳中我们获得了I3（迁移率Rm = 0.83、1.15和1.32）表型，这是南方根结线虫的典型表型，是用于将该物种与爪哇根结线虫区分开来的种特异性表型（1）。此外，雌成虫的排泄孔位于前端32.1（±5.4）μm处，与南方根结线虫的描述一致（25至53μm）（1）。据我们所知，这是南方根结线虫寄生普通菜豆根的首次报道。这一发现对巴西农业具有重要意义，因为这种线虫可能会损害普通菜豆植株，并成为该作物的另一个问题。为了阐明南方根结线虫对普通菜豆造成的损失，还需要开展更多工作。参考文献：（1）R. M. D. G. Carneiro等人，《线虫学》10:123，2008年。（2）P. R. Esbenshade和A. C. Triantaphyllou，《线虫学杂志》22:10，1990年。（3）K. M. Hartman和J. N. Sasser，载于《根结线虫高级论文集，第二卷 方法学》，K. R. Barker等人编，罗利：北卡罗来纳州立大学印刷厂，1985年，第115页。（4）巴西农业部，菜豆，巴西农业部。检索自http://www.agricultura.gov.br/vegetal/culturas/feijao，2012年9月5日。
