Distribution and population densities of citrus nematode [Tylenchulus semipenetrans (COBB, 1913) (Tylenchida:Tylenchulidae] in citrus growing areas of Aydin province

The aim of this study was to determine the distribution, population densities and infestation ratios of citrus nematode, (Tylenchulus semipenetrans) (Cobb, 1913) in citrus growing areas of Aydin province, Turkey. Soil samples were obtained from 10 different districts of Aydin province in fall 2014 and in summer 2015. According to analyzing of soil samples, the existence of the citrus nematodes was determined in 192 (88.88%) samples of 216 citrus areas. Infestation ratios of the citrus nematodes in the districts were 100% in Koçarlı, Köşk and Yenipazar; 93% in Nazilli; 91.38% in Kuyucak; 88.89% in Sultanhisar; 85.71% in İncirliova; 84.62% in Efeler; 83.33% in Kuşadası and 78.79% in Söke. The population densties of the citrus nematode were higher in the summer season compared to fall in term of the sampling times. The highest population density was detected in the orange orchards among citrus varieties. The highest population densities of the citrus nematodes were determined in Nazilli and Kuyucak as 1270 and 1276 individuals / 100 g soil, respectively. The data are a very close level to the economic damage threshold.