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

In a 6-year study of four nematode species in sod-based corn (Zea mays) rotations, population densities varied with different cropping systems. Continuous corn, with or without a winter rye (Secale cereale) or vetch (Vicia villosa) cover, favored an increase of Pratylenchus zeae and suppressed Trichodorus christiei, Helicotylenchus dihystera, and Xiphinema americanum. A four-year sod-based rotation (3 years sod, 1 year corn) of 'Coastal' bermudagrass (Cynodon dactylon) and fescue (Festuca arundinacea) was less favorable for P. zeae than was monocultured corn but was more favorable for T. christiei. Alfalfa (Medicago sativum) and rescue favored an increase of T. christiei but suppressed the other three species. 'Coastal' bermudagrass and 'Pensacola' bahiagrass (Paspalum notaturn) were not favorable for extensive development of any nematode species present. In longer term studies, of which these are a part, all four species survived for 10 years in relatively low numbers in bermudagrass and bahiagrass sods.