Chapter 22

Managing Nematodes in Vineyards

Nematode Species

Of the many genera of plant parasitic nematodes detected in vineyard soils, root-knot (Meloidogyne spp.), dagger (Xiphinema index), root lesion (Pratylenchus spp.), ring (Mesocriconema xenoplax), and citrus nematode (Tylenchulus semipenetrans) are the most important ones.

Root-knot Nematode (Meloidogyne spp.)

Root-knot nematodes (Meloidogyne spp.) are major pests of grapevines in most areas of the world. They are endoparasitic, penetrating into young feeder roots and inducing giant cell formation, usually resulting in root galls. The galls on small lateral roots may resemble a string of beads, and severe infestations may produce so many galls that whole rootlets become rough and thick. These galls interfere with water and nutrient uptake. Root-knot nematode galls can remain viable for several years, which provide an ongoing source of new nematode contamination. Cover crop species act as alternate hosts for these nematodes.

Dagger Nematode (Xiphinema spp.)

Dagger nematodes (Xiphinema spp.) are ectoparasites; they do not burrow into roots, but insert their long stylets deep into root tips, where they feed on root tip cells. Dagger nematode feeding causes limited necrosis and stunting and swelling of root tips.

Root-lesion Nematode (Pratylenchus spp.)

Root lesion nematodes (Pratylenchus spp.) are migratory endoparasites, burrowing into roots to feed, and migrating freely between root tissue and soil. Root lesion nematodes cause symptoms that range from many small lesions on young feeder roots to abnormal darkening and necrosis or death of the roots. They do not produce galls on the roots.

Ring Nematode (Mesocriconema xenoplax)

Ring nematodes (Mesocriconema xenoplax) are ectoparasites that feed on root cells, stressing the vine and causing yield reduction at high densities.

Citrus Nematode (Tylenchulus semipenetrans)

Citrus nematodes (Tylenchulus semipenetrans) are semi-endoparasitic causing stunting of grapevines and general deterioration of roots.

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