Repellent activity of eugenol on larvae of Rhipicephalus microplus and Dermacentor nitens (Acari: Ixodidae)

Abstract

The repellent activity of eugenol was evaluated on Rhipicephalus microplus and Dermacentor nitens larvae in a bioassay based on the vertical migration of these tick larvae during the host-seek phase. Solutions were used at concentrations of 10, 20, 30, 40, and 50 μl/ml and a control only with the solvent ethanol 50 GL. The larvae's reaction of climbing the rods of filter paper was observed each hour for 12 h and once more at 24 h. The repellence was calculated as a percentage through visual estimation, from the tendency of the larvae to climb the rods when the top part was impregnated with the eugenol solutions. For R. microplus larvae, the four highest concentrations produced repellence levels were greater than 80 % for up to 9 h. The repellence rates after 10 h for the concentration of 10 μl/ml was lower than 2 % (p > 0.05); and after 24 h, the values observed for the concentrations of 40 and 50 μl/ml were 77 and 80 % (p < 0.05). For the D. nitens larvae, the repellence was greater than 80 % for up to 5 h at the concentrations of 40 and 50 μl/ml; and after 9 h, the repellence fell for all treated groups were significantly different than the control were found only at the three highest concentrations. Therefore, eugenol has repellent activity on the larval stage of these two tick species, with the R. microplus larvae being more sensitive.

Assessment of the repellent effect of Lippia alba essential oil and major monoterpenes on the cattle tick Rhipicephalus microplus

“…In the present study, the repellent activity of L. alba essential oils from the LA‐13 and LA‐57 genotypes on R. microplus larvae was demonstrated until the last time‐point for which data were analysed (5 h: RC 50 = 2.19 mg/cm 2 and RC 50 = 5.07 mg/cm 2 , respectively) (Table ). These results showed lower repellent concentration than essential oils of Lindera melissifolia against Amblyomma americanum (Ixodida: Ixodidae) (Oh et al ., ) and the monoterpene eugenol against R. microplus and Dermacentor nitens (Ixodida: Ixodidae) (Zeringota et al ., ).…”

Association between olfactory sensitivity and behavioral responses of Drosophila suzukii to naturally occurring volatile compounds

“…Chemoreception plays a key role by regulating essential behaviors such as localization and discrimination of host plants suitable by females for laying eggs and by offspring as food source (Sollai, Biolchini, & Crnjar, 2018b). The goal of this study was to evaluate the olfactory sensitivity of D. suzukii females toward naturally occurring compounds, which showed deterrent or synergistic effects both in other species of insects and in different populations of D. suzukii (Del Fabbro & Nazzi, 2013; Kamsuk et al, 2007; Munerato et al, 2005; Park et al, 2016; Renkema et al, 2016; Renkema et al, 2017; Sobhy et al, 2017; Zeringota et al, 2013). First, we aimed at studying whether a relationship could be found between olfactory sensitivity and behavioral response to tested compounds.…”

“…Excluding cis ‐jasmone with 90% of purity, all compounds were purchased with a purity of ≥99% (GC) and used without further purification. These compounds were chosen on the basis of data available in the literature on different species of invertebrates: eugenol, a phenolic compound used in perfumes, flavorings, and as a local antiseptic and anesthetic (Jadhav, Khandelwal, Ketkar, & Pisal, 2004; Sell & Carlini, 1976), presents a repellent activity (Del Fabbro & Nazzi, 2013; Zeringota et al, 2013); menthol, the main component of peppermint essential oil (Ibanez & Amparo Blazquez, 2018), shows repellent activity (Park et al, 2016; Renkema et al, 2016; Renkema et al, 2017); vanillin, an aromatic compound and flavoring agent, shows the synergic effect with essential oils with repellent activity (Kamsuk et al, 2007); and cis ‐jasmone, a volatile compound that enhances the plant defense against herbivores and insects (Sobhy et al, 2017).…”

“…On the basis of these considerations, the aim of this study was to evaluate peripheral sensitivity of adult females of the spotted‐wing D. suzukii toward volatile compounds, which in other invertebrates and populations of D. suzukii have shown a repellent action (Del Fabbro & Nazzi, 2013; Kamsuk et al, 2007; Munerato, Sinigaglia, Reguly, & Rodrigues de Andrade, 2005; Park, Jang, Yoon, & Kim, 2016; Renkema et al, 2017; Renkema, Wright, Buitenhuis, & Hallett, 2016; Sobhy et al, 2017; Zeringota et al, 2013), by means of an electrophysiological and behavioral approach. In this respect, we evaluated the antennal olfactory sensitivity toward increasing concentrations of repellent compounds (both alone and as binary mixtures) and the subsequent ovipositing behavior evoked in adult females of D. suzukii .…”

“…These compounds are naturally occurring and showed biological activity in different studies aimed at developing control strategies of different pests. In fact, eugenol exhibited repellent action on larvae and adult ticks (Del Fabbro & Nazzi, 2013; Zeringota et al, 2013), and genotoxic effect on D. melanogaster (Munerato et al, 2005); vanillin increased the repellence times of DEET against mosquitoes (Kamsuk et al, 2007) and evoked the strongest antennal responses in adults of Philaenus spumarius (Germinara et al, 2017); menthol displayed moderate repellent action on D. suzukii populations in Canada (Renkema et al, 2016) and Republic of Korea (Park et al, 2016); finally, plants treated with cis ‐jasmone were more repellent to aphid Macrosiphum euphorbiae (Sobhy et al, 2017).…”