These roundworms (elders, roundworms, trichinae) belong to the most diverse and diverse group of animals in the world, which includes up to 20,000 different species. Most are very small from 0.1 to around a millimeter (the largest species with over 8 m lives in the sperm whale placenta). In contrast to more developed articular worms (such as the earthworm), they have no vessels. There are usually males and egg-laying females, but occasionally there is also a sexless virgin generation (pathogenesis). Four larval moultings are passed through until sexual maturity. The food is taken in through a hollow mouth prick, which moves rhythmically when sucking. They live in the soil with numerous species and also feed on bacteria or mushrooms what a positive element in ecological System of a Weingarten soil.
It was only in the 1930s that they became a pest grapevine recognized, until then it was wrongly assumed that phylloxera, In the vineyard there are mainly two groups that are directly affected by feeding damage and indirectly as a virus carrier for the Rebstock are very dangerous. As directly damaging parasites, the species Meloidogyne, Heterodera and Pratylenchus cause a defense reaction of the vine at the root tips Gallen which they then consume. Although this does not have as serious an impact as phylloxera, it does water stress and insufficient supply with nutrients, These small root bile occur mainly in sandy soil. The species Longidorus maximus and Rotylenchus borealis prick the vine roots directly with their mouth prick without gall formation, suck on them and destroy them. The shoots remain in development, in extreme cases the vine dies. The frequency of the damage is rather small.
The far more devastating effect is indirect, that is, the transmission of dangerous ones virus, The two species Xiphinema index or in German stiletto (comes only on the grapevine vor) and Xiphinema vuittenezi transmit the Grapevine fanleaf virus (GFV), the species Xiphinema diversicaudatum the Arabis mosaic virus (ArMV), both of which brushwood disease cause. As a preventive countermeasure, the use of nematode-resistant vine documents, These include the American species Vitis acerifolia. Vitis champinii. Vitis cinerea and Vitis mustangensis, An earlier common control by nematicides such as B. DBCP (dibromo-chloropropane) is no longer permitted in viticulture.
However, nematodes can be used as part of the Biological crop protection also as beneficials be used, there being special preparations for certain plants or pests such as weevil and owls caterpillars gives. A sachet can contain up to 2.5 million nematodes. The preparation is dissolved in water and sprayed. The living nematodes thus brought out actively look for the larvae or caterpillars in the soil, infest them and cause them to die within a very short time.