PATHOGENICITY OF 17 ISOLATES OF ENTOMOPHAGOUS NEMATODES (STEINERNEMATIDAE AND HETERORHABDITIDAE) FOR THE TICKS AMBLYOMMA-VARIEGATUM (FABRICIUS), BOOPHILUS-MICROPLUS (CANESTRINI) AND BOOPHILUS-ANNULATUS (SAY)

Entomopathogenous nematodes are well known biocontrol agents of insect s. They live in the superficial layer of the soil, a location where ti cks accomplish their molt and where they oviposit their eggs, making t hem, theoretically, the preys of infective larvae of nematodes. Sevent een strains of entomopathogenous nematodes: eight strains of Steinerne ma and nine strains of Heterorhabditis were placed in contact with eac h of the free living stages of three tick species: Amblyomma variegatu m, Boophilus microplus and B. annulatus. The first two species were re sistant to all the nematode strains that were tested, whereas B. annla tus was susceptible to all of them. Ovipositing females were more susc eptible than females during the preoviposition period. There were no a natomical differences between the two species of Boophilus which can a ccount for such differences in their susceptibility. The use of nemato des to control some species of ticks should be considered.