Population Dynamics of Plant Nematodes in Cultivated Soil: Effect of Sod-based Rotations in Tifton Sandy Loam.

In an 8-year sod-based rotation study, nematode population densities varied with different row-crop sequences and grass sods. In continuous row-crop rotations (cotton-corn-peanut), cotton and corn favored rapid increase of Belonolaimus longicaudatus and Trichodorus christiei. Numbers of Pratylenchus brachyurus were quite variable on all crops. Peanuts favored an increase of Criconemoides ornatum but suppressed the other three species. 'Coastal' bermudagrass supported more than twice the number of B. longicaudatus than did 'Pensacola' bahiagrass. Numbers of T. christiei and P. brachyurus also were larger on bermudagrass than on bahiagrass. Numbers of C. ornatum were largest in row-crop sequence culture. Average numbers of B. longicaudatus, T. christiei, and P. brachyurus in a sod-based, 3-years of row-crop sequence were smallest when cotton and corn did not follow each other. These nematodes were further suppressed when the sequence corn-peanut-cotton followed bahiagrass. Numbers of C. ornatum were smallest when corn and cotton followed each other, except after 3 years of bahiagrass. Nematode populations were less influenced by row-crop sequence following bermudagrass than they were following bahiagrass.