Table 2.

Results of the larval packet test with three strains of Rhipicephalus sanguineus larvae against fipronil

Acaricide	Strain	N	Slope (SE)	LC50 (95% CI) mg/ml	RR
Fipronil	UFRRJ	1526	1.646 (0.114)	0.029 (0.022–0.035) a	1.933
	RSPA	1614	3.935 (0.472)	0.007 (0.006–0.008) b	0.466
	CHRYSO	1289	4.405 (0.433)	0.015 (0.013–0.018) c	–

N number of larvae, SE standard error, LC50 median lethal concentration, 95% CI 95% confidence interval, RR resistance ratio; a, b, c: different letters represent significantly different LC50 values, based on the non-overlapping of 95% CIs