Long-term efficacy of Pochonia chlamydosporia, a fungal parasite of root-knot nematodes, was tested in two cropping systems: one consisting of three consecutive lettuce crops and another consisting of one tomato crop followed by two lettuce crops. Plants were either grown in pots in soil inoculated with 5000 chlamydospores of P. chlamydosporia per cm(3) soil or in soil without chlamydospores. Fifty or 25 second-stage juveniles (J2) of Meloidogyne javanica per 100 cm(3) soil were applied in Tests 1 and 2, respectively. The high nematode inoculum density of Test I resulted in considerable plant death, showing that the fungus was unable to control high nematode levels. At the harvest of most crop cycles, fewer J2 were found in soil or roots or fewer egg masses per root system were counted in pots with R chlamydosporia compared with pots without P. chlamydosporia. A one-time application of P. chlamydosporia was able to slow down the build-up of the M. javanica population for at least 5-7 months.