VERTICAL-DISTRIBUTION OF PLANT-PARASITIC NEMATODES IN SANDY SOIL UNDER MAIZE

Distribution of plant-parasitic nematode species at soil depths of 0-15 cm, 15-30 cm, and 30-45 cm was examined in two maize fields in Florida during 1987 and 1988. Soil type in both fields was an Arredondo fine sand, consisting of 94-96% sand at all three depths. On most sampling dates, more than 50% of the Belonolaimus longicaudatus collected occurred at the 0-15 cm depth. Only 20-30% of Criconemella sphaerocephala were present at this depth, and the depth distribution of this nematode differed in the two fields. The greatest densities of Pratylenchus brachyurus often occurred at 15-30 cm. Vertical distributions of Meloidogyne incognita and Paratrichodorus minor were erratic and showed marked seasonal variation. For all species examined except B. longicaudatus, a diagnostic soil sample collected 15 cm deep would recover only a minority of the nematode population present in the soil profile. © 1990 Kluwer Academic Publishers.