The essential oil from the leaves of Lippia gracilis was investigated for fumigant and residual activity against Tetranychus urticae (Acari: Tetranychidae) and Neoseiulus californicus (Acari: Phytoseiidae). The results were compared to eugenol, Ortus and Azamax, as positive controls. Gas chromatography (GC) and GC/mass spectrometry analysis enabled the identification of 28 compounds, accounting for 99.1 ± 0.6% of the essential oil. The major constituents were carvacrol (61%), p-cymene (11%) and thymol (11%). Mites were more susceptible to the oil in fumigant tests than in residual tests. Among the components, thymol and β-caryophyllene had the greatest fumigant and residual toxicity against T. urticae, respectively. The role of selected constituents (carvacrol, p-cymene, thymol, limonene, β-pinene, 1,8-cineole, terpinolene and β-caryophyllene) in the acaricidal properties of the L. gracilis essential oil is also discussed. Fumigant and residual effects of Lippia oil were more selective than eugenol with regard to a natural enemy of T. urticae, Neoseiulus californicus. Experiments under greenhouse conditions demonstrated greater toxicity of the Lippia oil in comparison to the positive control at 24, 48 and 72 h after treatment. The results suggest that Lippia oil is a good candidate for the formulation of a botanical acaricide for the integrated management of T. urticae.

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ABSTRACT. Development stadia of Anteos menippe (Hübner) (Lepidoptera, Pieridae) on Cassia ferruginea Shrad. (Caesalpinaceae), in laboratory. In order to determine the duration of the post-embryonic development and its instars, eggs of Anteos menippe were collected from Cassia ferruginea leaves and were taken into the laboratory to register the dates of ecdysis. The post-embryonic development was (in days average ± standard error) 25.7 ± 0.4, the larval period 15.9 ± 0.3 represented 61.7% of the development and had five instars: L1 = 2.2 ± 0.1, L2 = 1.7 ± 0.2, L3 = 2.0 ± 0.1, L4 = 3.4 ± 0.1 and L5 = 6.4 ± 0.3. This last instar had an active phase (5.4 ± 0.3) and a prepupal phase (1 day long). The pupal period was 9.9 ± 0.2. The inactivity period (prepupa + pupa) 10.9 ± 0.2 days represented 42.2% of the postembryonic development, and the active phase 57.8%. The egg viability was 91.6% and the survival, starting from neonate larvae, was 59.8%.

The fumigant action of peel essential oils of Citrus sinensis var. pear (pear orange = PO) and C. aurantium (bitter orange = BO) from the northeast of Brazil were evaluated against Bemisia tabaci biotype B and compared with eugenol as a positive control. The oil concentration in the PO at 8.5 μL/L of air caused 97% mortality, while the oil concentration of BO at 9.5 μL/L of air caused 99% mortality. However, the LC 50 estimates for both oils (LC 50 = 3.80 μL/L of air for PO and LC 50 = 5.80 μL/L of air for BO) did not differ from each other, but they did when compared with eugenol (LC 50 = 0.20 μL/L of air). Regarding their effects on oviposition, the Citrus oils showed concentration-response dependence, reducing the number of eggs as the concentration increased, which was not observed for eugenol. The minimum concentrations of the oils that caused a significant reduction in the egg lay were 3.5 and 7.0 μL/L of air for BO and PO, respectively. These results suggest that oils from PO and BO peels may be promising as models to develop new insecticides that might be applied into the integrated management of whiteflies.

This study describes the chemical composition of essential oils from the leaves of Protium aracouchine and Protium giganteum, evaluates their acaricidal properties and investigates the role of monoterpenes and sesquiterpenes in toxicity to Tetranychus urticae by fumigation and residual contact. The chemical analyses revealed that spathulenol (32.2 ± 1.6%) and β-caryophyllene (27.3 ± 1.1%) were the major constituents of the P. aracouchine and P. giganteum oils, respectively. Both Protium oils were toxic to the mite by fumigation and residual contact. The oils exhibited the same level of toxicity by residual contact, where the P. aracouchine oil was fivefold more toxic by fumigation than the P. giganteum oil. Among the chemical constituents tested, the mite was more susceptible to β-caryophyllene and spathulenol, independently of the method used. The blends prepared with terpenes selected from the P. giganteum oil had the same level of toxicity as the essential oil. The investigation of the role of terpenes in the form of blends revealed that β-caryophyllene and spathulenol contributed significantly to the acaricidal effects. These results suggest that the preparation of artificial oils is a promising strategy for the control of T. urticae.