Migratory endoparasitic nematodes.

Abstract

The morphology, life cycle, behaviour, dispersal, ecology, host range, distribution, molecular diagnosis, interaction with other parasites, and control (i.e. through cultural and chemical methods, and use of resistant crops) of lesion nematodes (Pratylenchus spp.), burrowing nematodes (Radopholus spp.), rice root nematodes (Hirschmanniella spp.), stem and bulb nematode (Ditylenchus dipsaci), bud and leaf nematodes (Aphelenchoides fragariae and A. ritzemabosi), A. besseyi, and pinewood nematode (Bursaphelenchus xylophilus) are described in this chapter.

Synergistic damage by interactions between Ditylenchus dipsaci and Rhizoctonia solani (AG 2–2IIIB) on sugar beet

“…These results supported the theory of Bergeson (1972) that the fungus opportunistically penetrates the plant through wounds caused by the nematode. Wounds caused by D. dipsaci on the petioles and the beet crown are favourable entry points for R. solani infection (Duncan & Moens 2006), which penetrates in the upper region of the beet body and at the base of the leaf petioles (Baker 1970, Herr 1996. The higher incidence of RCRR on plants infected with SBN supports the hypothesis that R. solani enters through holes in the epidermis created by the nematode.…”

“…Ditylenchus dipsaci juveniles of stage 4 penetrate aboveground plant parts early in the growing season, feed on the parenchyma, and destroy the middle lamella (Seinhorst 1957, Duncan & Moens 2006. Aboveground symptoms include small white callus pustules on the beet crown and distortion and bloating of leaf and petiole, which is followed by crown cancer development later in the growing season (Dunning 1957).…”

Analysis of the specificity of three root-feeders towards grasses in coastal dunes

“…This was expected for P. penetrans since it is an species reported in many different crops and grasses (Duncan and Moens 2006); far less knowledge was available for P. brzeskii and P. dunensis (de la Peña et al 2006a, b). Our results highlight clear differences in nematode multiplication as a function of the host and provide clear evidence for host specialization among the three species of Pratylenchus compared.…”

“…Pratylenchus brzeskii and P. dunensis are commonly found associated with two fore-dune grasses, A. arenaria and Elymus farctus (Viv.) Runemark ex Melderis, along the European Atlantic coast (de la Peña et al 2007;de la Peña et al 2006a) whereas P. penetrans is a cosmopolite species reported feeding in the roots of more than 400 plant species (Duncan and Moens 2006) and in dunes is usually associated with degenerating A. arenaria stands and Hyppophäe rhamnoides L. (Zoon et al 1993). Natural densities in foredune soils of Pratylenchus spp.…”

“…are a frequent component of nematode communities in crops (Duncan and Moens 2006), in temperate grassland ecosystems (de Goede and Bongers 1998) and also in coastal dunes (de la Peña et al 2007). These migratory endoparasitic nematodes invade, multiply, feed and move through the root cortex of the host plant (Zunke 1990) resulting in necrotic lesions which often promote secondary fungal infections (Back et al 2002).…”