Caracterizacao e ecologia de populacoes portuguesas de Trichodorus Spp. e Paratrichodorus Spp. (Nematoda: Trichodoridae)

Members of the genera Trichodorus and Paratrichodorus are well known as damaging a wide range of plant species either by direct feeding or by transmitting plant viruses: their economically important effects have been reported from various regions all over the world, since the middle of this century. However, in Portugal little was known about Trichodoridae until quite recently which has motivated the present research work aimed at initiating and developing research on those nematodes in Portugal. The main objectives were to investigate the morphological and morphometric variability of portuguese populations of Trichodorus spp. and Paratrichodorus spp., to evaluate the taxonomic value of some morphological and morphometric characters and to determine some possible relationships between ecological factors and the nematode populations. A survey was conducted in continental Portugal, during six years. Three hundred soil samples were taken in different localities and on various vegetation types. The soil was collected to a depth of about 10-30 cm, in the rhizosphere of the plants. The nematodes were extracted by a decanting and sieving technique. Trichodoridae nematodes were detected in 33% of the samples. In addition to Trichodorus and Paratrichodorus, the following genera of plant-parasitic nematodes were identified: Pratylenchus spp., Xiphinema spp., Paratylenchus spp., Helicotylenchus spp., Tylenchorhynchus spp., Globodera spp. or Heterodera spp., Helicotylenchus spp., Longidorus spp., Meloidogyne spp. and Ditylenchus spp. Paratrichodorus was the dominant genus, occuring in more than 3/4 of the samples with Trichodoridae..Available from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1249-074 Lisboa, Portugal / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga