Antagonistic activity of the fungusPochonia chlamydosporiaon mature and immatureToxocara caniseggs

Abstract

SUMMARYIn vitrotests were performed to evaluate the ability of 6 isolates of the nematophagous fungusPochonia chlamydosporiato infect immature and matureToxocara caniseggs on cellulose dialysis membrane. There was a direct relationship between the number of eggs colonized and the increase in the days of interaction, as well as between the number of eggs colonized and the increase in the concentration of chlamydospores (P<0·05). Immature eggs were more susceptible to infection than mature eggs. The isolate Pc-04 was the most efficient egg parasite until the 7th day, and showed no difference in capacity to infect mature and immature eggs in comparison to Pc-07 at 14 and 21 days of interaction, respectively. Isolate Pc-04 was the most infective on the two evolutionary phases of the eggs at most concentrations, but its ability to infect immature eggs did not differ from that presented by the isolates Pc-07 and Pc-10 at the inoculum level of 5000 chlamydospores. Colonization of infective larvae inside or outside the egg was observed in treatments with the isolates Pc-03, Pc-04, Pc-07 and Pc-10. The isolate Pc-04 ofP. chlamydosporiahas great biological capacity to destroy immature and matureT. caniseggs in laboratory conditions.