The occurrence and geographic distribution of Xiphinema and Xiphidorus species (Nematoda: Longidoridae) in Brazil
2003; De Gruyter Open; Volume: 40; Issue: 1 Linguagem: Inglês
ISSN
1336-9083
AutoresC. M. G. Oliveira, D. J. F. Brown, Roy Neilson, A. R. Monteiro, Luiz Carlos Camargo Barbosa Ferraz, F. Lamberti,
Tópico(s)Insect and Arachnid Ecology and Behavior
Resumo41 Summary The occurrence and geographic distribution of Xiphinema and Xiphidorus species were investigated during a national survey of 16 Brazilian States between 1999 and 2001. Eighty-two soil samples were collected from different habitats, including crop plants, grassland, savanna (cerra-do) and typical Amazonian forest vegetation. Fourteen Xi-phinema species ( X. brasiliense, X. brevicolle, X. elonga-tum, X. ensiculiferum, X. ifacolum, X. krugi, X. longicau-datum, X. paritaliae, X. setariae/vulgare complex , X. suri-namense, X. variegatum, and three morphotypes of X. ame-ricanum sensu lato identified as representing X. diffusum, X. oxycaudatum and X. peruvianum ) were recorded. Also, Xiphidorus balcarceanus , X. minor , X. yepesara parthenus and X. yepesara yepesara were identified from three States, however recognition of X. yepesara parthenus as a subspecies of X. yepesara requires confirmation. The most frequently occurring species were X. krugi (46 % of all samples), X. brasiliense (22 %) and X. setariae/vulgare complex (22 %). Xiphinema diffusum, X. longicaudatum, X. oxycaudatum, X. peruvianum and Xiphidorus balcar-ceanus constitute new records for Brazil. A principal com-ponent analysis identified odontostyle and odontophore length and to a lesser extent vulva position as the main influencing morphological characters that could be used to separate the Xiphinema and Xiphidorus species recorded in this study. A dichotomous key for the identification of Xiphinema species reported in Brazil is presented. Keywords: identification key; survey; taxonomy; virus vector nematodes; Xiphidorus; Xiphinema Introduction Xiphinema nematodes have a world-wide distribution and cause substantial damage to an extensive range of crop plants by their direct feeding on plant root cells (Taylor and Brown, 1997; Weischer and Brown, 2000) and affect-ing plant growth (Lamberti et al. 1987a; 1992a; 1992b; 1993; Leone et al., 1997; 1999). Also, several of these spe-cies are important economically as they are efficient vec-tors of several members of the genus Nepovirus that cause diseases in a wide range of fruit and vegetable crops (Brown et al. , 1995, 1996). In a comprehensive review, Doucet et al. (1998) reported that forty-two Xiphinema species occur in Latin America, with twenty-two (X. basiri, X. brasiliense, X. brevicolle, X. californicum, X. clavicaudatum, X. costaricense, X. dimi-diatum, X. elongatum, X. ensuculiferum, X. fluminense, X. georgianum, X. guillaumeti, X. ifacolum, X. index, X. kru-gi, X. machoni, X. pachtaicum, X. parasetariae, X. parita-liae, X. paulistanum, X. setariae/X. vulgare complex and X. surinamense ), including several virus-vector species, having been recorded in Brazil. Recently, another three species of Xiphinema ( X. torvum, X. variegatum and X. vi-carium) were reported from Brazil (Siddiqi, 2000). Xiphidorus nematodes that are indigenous to Latin Ameri-ca have a more restricted distribution as compared with Xiphinema, and the economic importance of these nemato-des with respect to crop damage is unknown (Leone et al., 1999). Currently, only eight Xiphidorus species have been identified from the following South American countries: Argentina, Brazil, Uruguay and Venezuela (Decraemer et al. , 1996; Coomans et al. , 1996; Doucet et al. , 1998; Lam-berti et al. , 1999) and an undescribed species from Bolivia (Hunt, 1993). In Brazil, X. amazonensis, X. minor, X. yepe-sara parthenus, and X. yepesara yepesara have been pre-viously recorded (Doucet et al. , 1998). Here we present data from a national survey of 16 Brazi-H
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