Repellency of MyggA® Natural spray (para-menthane-3,8-diol) and RB86 (neem oil) against the tick Ixodes ricinus (Acari: Ixodidae) in the field in east-central Sweden

In the field in south-central Sweden, we tested by randomised, standardised methodology the potential anti-tick repellent activity of two concentrations of MyggA® Natural spray (containing PMD) (4.2 and 3.2 g/m²) and one of RB86 (with 70% neem oil containing azadirachtin)(3 g/m²) to host seeking nymphs of Ixodes ricinus. Each substance was applied separately to 1 m² cotton flannel cloths. Nymphal ticks on the cloths, pulled over the vegetation, were recorded at 10-m stops. Nymphal numbers recorded differed significantly between treated cloths [4.2 or 3.2 g MyggA® Natural spray/m² and 3 g RB86/m²] and the untreated control (df = 3, χ² = 112.74, P < 0.0001). Nymphal numbers also differed significantly among collectors (df = 3, χ² = 15.80, P < 0.001). Repellency of treated cloths, i.e., 4.2 or 3.2 g MyggA® Natural spray/m² and 3 g RB 86/m² declined from day 0 (i.e. the day of impregnation) to day 3 after impregnation from 77 to 24%, 58 to 16% and 47 to 0.5%, respectively. This study suggests that all three treatments have significant repellent activities against I. ricinus nymphs.