Metarril SP Organic is a product based on the fungus Metarhizium anisopliae, which was developed for controlling agricultural pests. The present study evaluated the effect of Metarril SP Organic plus 10% mineral oil, for controlling Rhipicephalus microplus under field conditions. Three groups were formed: Control group, which received no treatment; Oil control group, which was bathed only with water, Tween 80 and mineral oil; and Metarril group, bathed in the oil-based formulation Metarril SP Organic. Two treatments per group were performed and to verify the effect of the treatments, all R. microplus ticks between 4.5 and 8.0mm in length on the left side of the cattle were counted on days +7, +14 and +21 after each treatment, and a sample of engorged females was collected for evaluation of biological parameters. The Metarril SP Organic oil formulation showed efficacy ranging from 8.53 to 90.53%. The average efficacy of the oil-based formulation of Metarril SP Organic was 75.09 and 46.59% compared with the groups Control and Oil control, respectively. There were no significant changes in biological parameters of engorged R. microplus females collected from animals. Although there was no significant difference in the amount of ticks between the Oil control and Metarril groups, it is believed that the association of mineral oil with Metarril SP Organic product is effective in R. microplus tick control in field. Thus, this association has potential to be used in strategic control programs of cattle tick.

This study evaluated the influence of alternate insects hosts Mahanarva spectabilis and Galleria mellonella on the efficacy the entomopathogenic nematode, Heterorhabditis baujardi isolate LPP7, for Rhipicephalus microplus control. In the first experiment, engorged R. microplus females were exposed to entomopathogenic nematode H. baujardi LPP7 with or without the presence of M. spectabilis nymphs or G. mellonella larvae. There were also groups containing only M. spectabilis or G. mellonella exposed to H. baujardi and a control group for each arthropod. In the second experiment, engorged females were exposed to different concentrations of H. baujardi which were reared from M. spectabilis and G. mellonella. Mortality rates of engorged R. microplus females, held together with EPN-infected M. spectabilis or G. mellonella inside, was 100% after five days, while the group containing only ticks reached 86%. EPNs caused reduction (p < 0.05) in the amount of eggs produced by engorged females. In the second experiment, the use of nematodes reared in M. spectabilis and G. mellonella also caused a decrease (p < 0.05) in the egg mass weight of R. microplus. The inhibition rate of egg-laying was greater than 80% for all treatments, reaching 92% in the treatment at a concentration of 800 EPNs/female, with nematodes reared in G. mellonella. We can conclude that, under laboratory conditions, the presence of another host did not reduce the activity of H. baujardi on R. microplus. Infective juvenile of entomopathogenic nematodes reared in M. spectabilis or G. mellonella have similar virulence against R. microplus engorged females.