Association between entomopathogenic nematodes and fungi for control of Rhipicephalus microplus (Acari: Ixodidae)

The aim of the study was to assess the effect of the association of entomopathogenic nematodes and fungi on Rhipicephalus microplus. The nematodes used were Heterorhabditis bacteriophora HP88 and Heterorhabditis indica LPP1 and the fungi were Metarhizium anisopliae IBCB 116 and Beauveria bassiana ESALQ 986. In the groups treated with the fungi, the females were immersed for 3 min in a conidial suspension, while in the groups treated with the nematodes, the ticks were exposed to infective juveniles. To evaluate the interaction between entomopathogens, the females were first immersed in a conidial suspension and then exposed to the nematodes. The egg mass weight and hatching percentage values of the groups treated with M. anisopliae IBCB 116 and B. bassiana ESALQ 986 in the two experiments were statistically similar (p > 0.05) to the values of the control group. In the groups treated only with nematodes, there was a significant reduction (p < 0.05) in the egg mass weight, a fact also observed for the hatching percentage of the group treated with H. indica LPP1. In all the groups treated with nematodes in association with fungi, there was a significant reduction (p < 0.05) in the egg mass weight and hatching percentage. The percentage of control of the groups treated with fungi alone varied from 31 to 55 %. In the groups treated with nematodes associated or not with fungi, the control percentage was always greater than 90 % and reached 100 % in the group treated with H. bacteriophora HP88 associated with the fungus M. anisopliae IBCB 116.