PLANT-PARASITIC NEMATODES ASSOCIATED WITH COTTON IN FLORIDA

A sampling of 15% of the cotton hectarage in each Florida county was a ssayed for nematodes and soil particle components following the 1990 h arvest. The distribution of juveniles of Meloidogyne spp., which were found in 61% of the 178 fields sampled statewide, was not influenced b y soil type. Rotylenchulus reniformis was more prevalent in the heavie r soils and occurred in 15% of the sampled fields. In fields with conc omitant infestations (9% of the sampled fields), densities of root-kno t juveniles per 10 cm(3) soil were negatively related to those of reni form nematodes (R(2) = -0.32; P < 0.02; df = 14). Gall ratings of cott on plants, assayed in sampled soils, were positively related to the de nsities of root-knot juveniles per 100 cm(3) soil (R(2) = 0.23; P < 0. 01; df = 175). Other nematode genera and their frequency of occurrence were Helicotylenchus (76%), Paratrichodorus (57%), Criconemella (53%) , Pratylenchus (42%), Xiphinema (7%), Heterodera (2%), and Hoplolaimus (1%).