ABSTRACT: The citrus leafminer,Phyllocnistis citrella Stainton,is native to southern Asia and regarded as an important pest in nurseries and young or top-worked citrus trees in Florida. Although various biotic mortality factors have been cited, their relative effect and impact on P. citrella populations in the field has not been clear. We used direct observation and exclusion methods to evaluate the individual contributions of predation and parasitization on leaf miner populations in the field. Ant predation was the largest single cause of mortality, accounting for more than 30% of all deaths by natural enemies, and 60% of all death by predators. Early (1st and 2nd stage) instars were most subject to ant predation. Ageneaspis citricola was the most important parasitoid of P. citrella contributing 8.2-28.6% mortality compared to 9.6-14.7% mortality from indigenous parasitoids. The total impact of biotic mortality was 65-70%.