title: [Some observations on the influence of ecological factors on the occurrence and the distribution of plant parasitic nematodes in the Democratic Republic of Sudan].
abstract: Among the various ecological factors influencing the phytonematode fauna the types of plant and soil determine the nematode range. Radopbolus similis, Helicotylencbus multicinctus, Hemicriconemoides strictatbecatus, Ditylencbus augustus, Tylencbulus semipenetrans, and possibly Paratropburus kenanae are examples of high host specificity. The Pratylencbus, Meloidogyne, Xipabenema, as well as certain Tylencborbyncbus species differ in their demands to the soils. Non-irrigated natural locations exhibit a direct dependence of the range of species on the amount of precipitation, as can be seen from examples from the < 300 mm, 300 to 400 mm, and > 500 mm- annual precipitation ranges. Regions irrigated regularly correspond to the last-mentioned group. The moisture content depending on the annual floodings in the Gash and Baraka deltas has to be classified as a separate and special case. There are no sufficient findings available on the influence of the temperature and of the harmful organisms. They exert a stronger influence on the population density than on the range of species.
mesh_terms: D000818:Animals; D011232:Chemical Precipitation; D009348:Nematoda / Q000302:isolation & purification*; D010944:Plants / Q000382:microbiology*; D012988:Soil Microbiology; D013397:Sudan; D013696:Temperature
vernacular_title: Einige Beobachtungen über den Einfluss ökologischer Faktoren auf das Vorkommen und die Verbreitung pflanzenparasitäter Nematoden in der Demokratischen Republik Sudan.