Seasonal population dynamics of selected plant-parasitic nematodes on four monocultured crops.

Seasonal fluctuations in field populations of Meloidogyne incognita, Pratylenchus zeae, P. brachyurus, Criconemoides ornatus, Trichodorus christiei, and Helicotylenchus dihystera on monocultured corn, cotton, peanut, and soybean were determined monthly for 4 yr. Population densities of M. incognita were greater in corn and cotton plots than in peanut and soybean plots from July until January. Those of Pratylenchus spp. were greater on corn and soybean than on cotton and peanut during all months except May and June. C. ornatus populations were greater on corn and peanut than on cotton and soybean during all months. C. ornatus on corn and peanut was more numerous in July than in other months. There was no significant increase in populations of T. christiei, except on corn in June. H. dihystera was greater in cotton and soybean plots than in corn and peanut plots from August through December.