Population densities of plant-parasitic nematodes were monitored for two seasons in plots with winter cover crops of rye (Secale cereale) or hairy vetch (Vicia villosa) on sandy soils in north central Florida. The ranges in nematode densities observed in the plots permitted derivation of linear relationships between final population densities (Pf) after 3 and 5 months and initial population densities (Pi) before planting of cover crops in October or November. More consistent linear relationships (P 0.05) were obtained for Belonolaimus longicaudatus and Criconemella sphaerocephala than for Meloidogyne incognita and Pratylenchus brachyurus. In most instances, population densities were maintained by the cover crops, with Pf Pi. However, maintenance of a rye cover crop for almost 5 months resulted in increased B. longicaudatus densities, with Pf or Pi or 3 Pi, depending on the season.
