Evaluation of Insecticidal Activity of Thyme, Oregano, and Cassia Volatile Oils on Cat Flea

Abstract

The aim of the present study was to evaluate the insecticidal effect of the cassia, thyme and oregano volatile oils against the immature and adult flea's stages. For this purpose, the tested samples were chemically characterized by GC-FID and GC-MS. The mortality of larvae and adult fleas, eggs, and pupae of Ctenocephalides felis felis was performed through in vitro tests at different concentration levels. Inhibition of development and residual efficacy were also determined. The chemical characterization of the cassia, thyme, and oregano volatile oils presented cinnamaldehyde (91%), thymol (44.7%), and carvacrol (76.2%), respectively, as major constituents. In general, the samples showed insecticidal activity for both immature and adult flea's stages. The best LC 50 values for adults were obtained by oregano volatile oils (33.5 and 21.8 μg•cm −2 , respectively, 24 and 48 h). Cassia volatile oils showed the best results against larvae (17.2 and 10.3 μg•cm −2 , respectively, 24 and 48 h), eggs (3 μg.cm −2), and pupae (34.6 μg•cm −2), as well as the lowest value for inhibition of development (2.3 μg•cm −2). The oregano and thyme volatile oils showed residual efficacy greater than 80% for 6 days while cassia showed this result for 4 days. The results demonstrated the potential of volatile oils for flea control in all stages of the life cycle, with emphasis on cassia. The residual effects of the volatile oils are promising for the development of new and environmentally friendly phyto-pesticides for veterinary uses.

Efficacy and residual effect of Illicium verum (star anise) and Pelargonium graveolens (rose geranium) essential oil on cat fleas Ctenocephalides felis felis

“…The in vitro activity of the essential oils against immature stages of C. felis felis was evaluated using filter paper tests against (Conceição et al, 2020) eggs, larvae and pupae. The inhibition of flea development was also analyzed.…”

“…In vitro insecticidal activity against C. felis felis adults was evaluated using the impregnated filter paper technique (Conceição et al, 2020) against unfed fleas obtained from the laboratory colony. The impregnated and dried strips were inserted into glass tubes containing 10 unfed adult cat fleas (five males and five females).…”

“…The residual efficacy of the essential oils against adults of C. felis felis was assessed by means of the filter paper impregnation technique (Conceição et al, 2020) against unfed fleas. The impregnated and dried strips were inserted into glass tubes containing 10 unfed adult cat fleas (five males and five females).…”

“…These can be applied by industry, food and pharmaceuticals (Dawood et al, 2021). Activity of essential oils against fleas has been reported (Lambert et al, 2020;Dos Santos et al, 2020;Conceição et al, 2020). It is believed that these oils can act by means of several mechanisms, since the chemical composition of essential oils is complex, possibly including mono and sesquiterpenes and/or phenylpropanoids.…”

New carvacrol and thymol derivatives as potential insecticides: synthesis, biological activity, computational studies and nanoencapsulation

“…13,14 Carvacrol (5-isopropyl-2methylphenol) and thymol (2-isopropyl-5-methylphenol) are important phenolic monoterpenes obtained from the essential oil of some Laminaceae members, such as oregano, thyme, and savory, functioning as a chemical defence mechanism against phytopathogenic microorganisms. [15][16][17][18][19][20][21] In addition to other monoterpenes, carvacrol and thymol have been structurally modied to enhance their biological activities. 22,23 For example, carvacrol, thymol and their derivatives have demonstrated larvicidal activity against Aedes aegypti.…”