OCCURRENCE OF THE CITRUS NEMATODE IN OLD CITRUS GROWING REGIONS OF FLORIDA

Citrus nematodes (Tylenchulus semipenetrans) were found in 45 of 50 ma ture citrus groves during a survey conducted in five central, eastern coastal and southwest Florida counties. From a total of 1000 samples t he citrus nematode was detected in 475 and 548 soil and root samples, respectively. Approximately half of the infested groves contained tree s beneath which no citrus nematodes were found. Many infested groves c ontained a patchy distribution of infested trees, possibly from random inoculation events. Linear correlations existed between citrus nemato de population densities and levels of soil K, Cu, and soluble salts in the Flatwoods counties. In the Central Ridge counties, nematode densi ty was correlated with levels of soil P and K.