Soil Types and their Physio – Chemical Properties for Population Development of Root Knot Nematode (Meloidogyne spp.) in Tomato (Solanum lycopersicum)

Root Knot Nematodes (RKN) (Meloidogyne spp.) is the major soil borne microorganisms causing severe losses in vegetable production in Sri Lanka. This experiment was conducted to determine the effect of the fourteen different soil types and their physio-chemical properties for population development of Meloidogyne spp on tomato crop. The population of RKN showed significant differences among different soil types. The maximum nematode population (Root Galling Index of 7.25, Number of knots of 165.25) were recorded in Red Yellow Podzolic – Imperfectly Drained soil with higher organic carbon (11.54%), phosphorus (3.30 ppm), potassium (369 ppm), sand (77.06%), moisture content (16.22%) and it was not significantly difference between Red Yellow Podzolic – Imperfectly Drained soil and Regosol. The minimum nematode population (Root Galling Index of 2.75, Number of knots of 51.75) was recorded in Reddish Brown Latosol – Imperfectly Drained soil with organic carbon (4.1% w/w), phosphorus (0.58 ppm), sand (64.66%), and moisture content (6.19%). Analysis of correlation coefficient showed that population of Meloidogyne spp. significantly positive correlated with phosphorus, potassium, nitrogen, EC, soil moisture and sand percentage while significantly negative correlated with the silt + clay percentage, soil temperature and soil pH. There was no significant correlation recorded with soil organic carbon content as it was clearly indicated that all the samples had very low percentage of organic carbon in compared to suppressive soils. Therefore, the study concludes all soil physic-chemical properties except organic carbon have direct effect on the development of population of Meloidogyne spp. and it is varied with the different soil types, hence it is vital to contemplate soil type and its physio-chemical properties when executing Integrated Nematode management programs for Meloidogyne spp. However, further Investigations are required to study the direct effect of soil organic carbon on development of population of Meloidogyne spp.