Abstract
Background: For cattle producers, ticks and tick-borne diseases are a severe economic and public-health problem. The emergence of acaricide resistance to synthetic chemical treatments has prompted interest in the development of alternative tick control methods.
Aim: The main objective of the current research was to identify the chemical structure of Carthamus tinctorius and Nasturtium officinale seed oils and to assess their anti-tick properties against Hyalomma scupense ticks both alone and in combination (1 :1).
Methods: Analytical method were used to analyze the chemical components. For in vitro assays, adults of H. scupense were immersed in C. tinctorius and N. officinale seed oils at 100, 125, 200 and 300 mg/mL concentrations; for 5 min. Larvae of H. scupense were dipped in 25, 50, 100, 125, 200 and 300 mg/mL doses of seed oils; the mortality percentage was determined after 24 hours.
Results: The seed oil safflower was mainly composed of linoleic acid (84.48%) followed by palmitic acid (6.54%) and stearic acid (3.77%). Meanwhile, watercress seed oil was mainly composed of linolenic acid (50.78%), gondoic acid (13.57%), linoleic acid (10.58%), palmitic acid (8.02%) and erucidic acid (6.62%). The Adults Immersion Test carried out showed sensitivity of ticks to C. tinctorius and N. officinale seed oil: C. tinctorius seed oil caused mortality of H. scupense (95%) of mortality at 300 mg/mL. While, N. officinale seed oil induced (88.68%) mortality at same concentration. At a concentration of 200 mg/mL, a combination of C. tinctorius and N. officinale oil caused 100% mortality. Tested oils showed larvicidal efficacy. LC50 values for C. tinctorius and N. officinale seed oils were 84.16 mg/mL and 61.78 mg/mL, respectively, in 24 hours. LC50 value of oils association (50% C. tinctorius: 50% N. officinale) was 47.96 mg/mL.
The mixture of seed oils from two plants tested against H.scupense larvae and adult females at 1:1 ratio showed synergistic interaction.
Conclusion: seed oils tested alone and mixture could be used as an alternative solution in the fight against ticks.

Key words: : Carthamus tinctorius, H.scupense, Nasturtium officinale, acaracidal activity, synergistic.