Population fluctuation of three parasitic nematodes in Florida citrus

In Florida, Tylenchulus semipenetrans on citrus has two high and two low population levels each year. High levels occur in April-May and November-December, and low levels, in February-March and August-September. Population increases occur about 4-5 weeks after the spring and fall flush of root growth. Populations of Pratylenchus coffeae on citrus varied widely, and were not related to season. Populations of P. brachyurus showed seasonal variation with a high in June-July and a low in March-May. Males of T. semipenetrans and P. coffeae were found throughout the year, whereas males of P. brachyurus were rare and were found only during November and December.