Interacting Effects of Soil Texture and Inoculum Levels on Reproduction and Pathogenicity of Meloidogyne javanica on Potato

A 2-year study was conducted in the greenhouse to determine the effects of three soil types ( sand, sandy loam and loam ) and four inoculum levels ( 0, 1000, 2000 and 4000 nematode eggs / 500 cm3 soil ) of Meloidogyne javanica on nematode reproduction and pathogenicity on potato cv. Spunta. Nematode reproduction and host damage were both affected by the soil texture and the initial inoculum level. Number of egg masses, eggs and galls across all soil types increased ( P = 0.05 ) as the inoculum level increased. The least ( P = 0.05 ) nematode reproduction and host damage occurred in the loam soil. The sandy and sandy loam soils showed higher nematode reproduction and damage with no significant differences. Regression analyses of the independents Pi-sand-clay vs. number of eggs and galls gave R2 values of 0.45 and 0.56, respectively. The R2 for Pi alone vs. eggs was 0.39 and vs. galls 0.52. Soil affected tuber yield with the least fresh tuber weights occurring in the loam soil. The R2 for Pi-sand-clay vs. yield was 0.13