Geographical distribution of root lesion nematode, Pratylenchus loosi, and study on correlation of soil physico chemical properties with level of population in tea plantation of Iran

The root canal nematode, Pratylenchus loosi, is the most important causative agent in tea gardens in the north of the country. Dispersion and its relationship to the physical and chemical properties of soil and the amount of soil nutrients in Iran have not been studied. The aim of this study was to investigate the spread of tea gardens to this nematode and its correlation with physical and chemical properties of soil. For this purpose, soil and roots were collected from all of the regions in which tea was planted in Guilan and Mazandaran provinces. The nematodes were extracted from soil and tea. In addition to soil nutrients (nitrogen, phosphorus and potassium), organic carbon, pH and soil texture were also determined. The whole Data, soil characteristics and nematode populations were mapped to the Arc GIS environment according to the spatial coordinates of each point using the Kriging estimator. The results showed that the frequency of nematode population in eastern Gilan (75%) is almost twice greater to western Guilan (31%). There is a weak correlation between nematode population and soil characteristics. But the geographic distribution of the nematode population has simultaneously harmony with some soil characteristics. In the eastern regions, severe and moderate contamination occurs in soils with a pH less than 4.5, gravel higher than 65%, silt less than 18%, and organic carbon less than 2.1%.Keywords: Tea, Nemateds, pH, Soil notrients.