Nematodes

Nematoden
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This turning round and usually about one millimeter (rarely up to 12 mm) long thread worms (nematodes, roundworms, trichina), among the lower worms. Unlike more sophisticated segmented worms (such as the earthworm) they have no vessels. Usually there are males and egg-laying females, but occasionally a sexless Virgin procreation (Pathenogese). To sexual maturity are run through four larval molts-. Food intake is through a hollow spike mouth that moves while sucking rhythmically. They live with many species in the soil and also of Bacteria and mushrooms , which in this case, a positive element in the ecology of.

In vineyards are found mainly two types of groups that directly and indirectly through feeding damage are very dangerous viruses as vectors for the vine. As a direct harmful parasites cause the species Meloidogyne, Heterodera and Pratylenchus as a defense reaction of the vine to the root tips Gall They eat it. This is not as serious as the effects of phylloxera leads, but Water stress and insufficient supply of Nutrients . These so-called root-occur, especially in sandy soil. The species Longidorus maximus borealis and Rotylenchus prick with her mouth directly on the sting vine roots without galls, suck it and destroy it. The shoots are left behind in development, in extreme cases, die from the vine. From the frequency of occurrence ago that these losses are fairly low. By far the most devastating effect is indirect, ie, by transfer of virus or Virus complexes.

The species of Xiphinema index or German Stilettälchen (occurs only on the vine) and Xiphinema transmitted vuittenezi the Grapevine fanleaf virus (GFV), the species Xiphinema diversicaudatum the Arabis mosaic virus (ArMV), both of the leafroll effect. As a preventive measure defense applies in particular the use of nematode-resistant vine documents. These are the American species Vitis acerifolia (Vitis longii) Vitis champinii , Vitis cinerea and mustangensis Vitis (Vitis candicans). A former practice of control by nematicides such as the DBCP is no longer allowed in the wine. See also Vine-enemies .