Ditylenchus Dipsaci (Kuhn) Filipjev. is one of the most destructive nematodes to crop plants. It attacks and damages more than 300 species of cultivated and uncultivated plants. The nematode can be differentiated into many races, each of them having a preference for a group or even a single plant species. Alfalfa stem nematode is one of the races in this species which attacks the above ground portion of alfalfa but does not infest the roots. Larvae of this nematode may migrate from the plant tissue to soil in moist conditions. These nematodes migrate actively to nearby plants or are carried by agricultural tools or wind to reach plants at some distance away, causing a new infection.

Made available in DSpace on 2014-06-11T19:33:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-11-06Bitstream added on 2014-06-13T19:23:57Z : No. of bitstreams: 1 gonzaga_v_dr_jabo.pdf: 2262058 bytes, checksum: 9f1c54256f73cca2fe58faf334cc3382 (MD5) / Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) / Os nematóides das lesões radiculares (Pratylenchus spp.) são considerados o segundo grupo de fitonematóides de maior importância econômica em todo o mundo. A morfologia e a morfometria das seis espécies mais comuns desses nematóides, no Brasil, a saber: Pratylenchus brachyurus, P. coffeae, P. jaehni, P. penetrans, P. vulnus e P. zeae, foram estudas aos microscópios óptico composto e eletrônico de varredura. Os dados foram analisados, também, por análise discriminante e análise canônica, tendo sido determinada uma equação da função de classificação para cada uma das espécies. Conquanto cada uma das espécies possa ser identificada por qualquer das ferramentas utilizadas, a análise morfológica, a análise morfométrica, assim como as análises discriminante e canônica devem ser consideradas ferramentas complementares no processo de identificação das espécies, aumentando a confiabilidade da identificação. Uma grade politômica ilustrada para identificação rápida dessas espécies foi elaborada. A técnica de multiplicação in vitro dessas espécies em cilindro de cenoura mostrou-se adequada para produção massiva desses nematóides, sendo que P. penetrans e P. jaehni foram as espécies que produziram, respectivamente, o maior e o menor número de indivíduos e ovos por cilindro de cenoura, aos 120 dias após a inoculação. / The lesion nematodes (Pratylenchus spp.) are considered the second largest group of plant parasitic nematodes of economic importance in the world. The morphology and morphometry of the six more common species of these nematodes in Brazil, namely: Pratylenchus brachyurus, P. coffeae, P. jaehni, P. penetrans, P. vulnus and P. zeae, were studied at the light and scanning electron microscopes. The data were also submitted to discriminant and canonical analyses and an equation of the classification function for each one of the species was determinated. Althought each one of the species can be identified by any of the tools used, the morphologic and morphometric analyses, as well as the discriminant and canonical analyses, must be considered complementary tools in the process of species identification, thus increasing the reliability of the identification. An illustrated polytomous key for a fast identification of these species was elaborated. The in vitro multiplication technique of these species in carrot cylinder was suitable for massive production of these nematodes. Pratylenchus penetrans and P. jaehni were the species that produced, respectively, the greatest and the smallest number of individuals and eggs for carrot cylinder, 120 days after the inoculation.