Comparative toxicity of essential oil and blends of selected terpenes of Ocotea species from Pernambuco, Brazil, against Tetranychus urticae Koch

Abstract

Essential oils from the leaves of two species of the genus Ocotea that occur in the Atlantic Forest in the state of Pernambuco, Brazil, were analyzed using gas chromatography-mass spectrometry. The acaricidal activity of these oils as well as 11 selected components and blends were evaluated in fumigation and residual contact tests against the two-spotted spider mite (Tetranychus urticae). Sixty-seven constituents were identified, totaling 97.3 ± 0.3% and 97.8 ± 0.5% of the oils from O. duckei and O. glomerata, respectively. Sesquiterpene was the dominant class. The compounds β-caryophyllene (18.6 ± 0.1%) and aromadendrene (17.3 ± 0.6%) were the main constituents of the oils from O. duckei and O. glomerata, respectively. Acaricidal action varied depending on the method employed, species and chemical nature of the selected constituents. The mites were susceptible to the oils and chemical constituents using the fumigation method. The O. duckei oil was respectively 2.5-fold and 1.5-fold more toxic than the O. glomerata oil using the fumigation and residual contact methods. Among the selected constituents, β-caryophyllene was the most toxic, independently of the method employed. The individual toxicity of the selected compounds and their blends as well as the role of these constituents in the overall toxicity of the essential oils are also discussed.

Chemical Diversity and Biological Activities of Essential Oils from Licaria, Nectrandra and Ocotea Species (Lauraceae) with Occurrence in Brazilian Biomes

“…Sesquiterpene hydrocarbons showed percentages of 55.7% and 78.15% in EOs of individuals of Ocotea duckei Vattimo collected in Camocim de São Felix (PE) and Santa Rita (PB), respectively. β-Caryophyllene (18.1%) and valencene (17.6%) are the main compounds for the first one and β-caryophyllene (60.54%) for the second [ 37 , 38 ]. The EOs of two specimens of Ocotea gardneri (Meisn.)…”

“…The specimen collection site was not reported [ 41 ]. Leaves of Ocotea glomerata (Nees) Mez collected in Camocim de São Felix (PE) had 64.8% of sesquiterpene hydrocarbons with a predominance of aromadendrene (17.3%) and β-caryophyllene (14.6%) [ 37 ].…”

“…The EO from the leaves of the specimen from Santa Rita (Atlantic Forest biome, PB) showed high content of β-caryophyllene (60.54%), followed by minor amounts of α-humulene (4.63%), and δ-selinene (4.4%) (profile I) [ 38 ]. The profile reported for the oil of a specimen collected in Camocim de São Félix (Caatinga biome, PE) was rich in β-caryophyllene (18.1%), valencene (17.6%) and elemol (6.8%) (profile II) [ 37 ].…”

Analysis of the Essential Oils ofEucalyptus camaldulensisDehnh. andE. viminalisLabill. as a Contribution to Fortify Their Insecticidal Application

“…28,34 Due to lower vapor pressures, high contact toxicity, and moderate fumigant pesticidal activities of sesquiterpenes, such as aromadendrene and spathulenol identified in the present research, were also reported. 31,35 Consequently, the promising fumigant toxicity of E. camaldulensis and E. viminalis essential oils may be associated with high percentages of the above-mentioned monoterpenes. However, synergistic, additive, and antagonistic effects all components should be considered in the essential oil activities.…”

“…36 Fumigant and contact toxicity against the nymphs and adults of Blattella germanica L. 28 Aromadendrene Fumigant and contact toxicity against the adults of Tetranychus urticae Koch. 35…”