Lethal and Sublethal effects of four essential oils on the egg parasitoids Trissolcus basalis

The essential oils from leaves of Schinus molle var. areira, Aloysia citriodora, Origanum vulgare and Thymusvulgaris have showed potential as phytoinsecticides against the green stink bug, Nezara viridula. In thiswork were evaluated their toxicological and behavioral effects on the parasitoid Trissolcus basalis, a biological control agent of this pest insect. Essential oils were obtained via hydrodestillation from fresh leaves.Insecticide activity in T. basalis females was evaluated in direct contact and fumigation bioassays. Behavioral effects were evaluated in olfactometer bioassays. To evaluate the residual toxicity, females of the parasitoids were exposed to oil residues; in these insects, the sublethal effects were evaluated (potential parasitism and survivorship of immature stages). The essential oils from O. vulgare and T. vulgaris proved to be highly selective when used as fumigant and did not change parasitoid behavior. After one week, the residues of these oils were harmless and did not show sublethal effects against T. basalis. According with these results, essential oils have potential applications for the integrated management of N. viridula.Fil: Werdin Gonzalez, Jorge Omar. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; ArgentinaFil: Laumann, Raul Alberto. Embrapa Recursos Genéticos e Biotecnologia; BrasilFil: Da Silveira, Samantha . Embrapa Recursos Genéticos e Biotecnologia; BrasilFil: Blassioli Moraes, Maria Carolina . Embrapa Recursos Genéticos e Biotecnologia; BrasilFil: Borges, Miguel . Embrapa Recursos Genéticos e Biotecnologia; BrasilFil: Ferrero, Adriana Alicia. Universidad Nacional del Sur; Argentin

Ultrasound assisted formation of essential oil nanoemulsions: Emerging alternative for Culex pipiens pipiens Say (Diptera: Culicidae) and Plodia interpunctella Hübner (Lepidoptera: Pyralidae) management

Over the last years, nanotechnology has contributed to the development of new botanical insecticides formulations based on essential oils (EO), which are safe for the human health and the environment. Nanoemulsions (NEs) can enhance the bioactivity of the EO to prevent the premature volatility and degradation of the active ingredients. In our work, geranium EO (Geranium maculatum L.) was used to develop micro and nanoemulsions adding Tween 80 as surfactant. For NEs formulation, ultrasound was applied and the physicochemical and ultrasound parameters were optimized: oil: surfactant ratio = 1:2, ultrasound power = 65 W, sonication time = 2 min, cycles = 30 on/20 off and ultrasonic probe distance = 3.7 cm. The NEs obtained had 13.58 nm and polydisperse index (PDI) values of 0.069. They were stored at 25 °C and were stable for 60 days. The present study also demonstrated the potential of NEs to enhance the toxicity of geranium EO against larvae of Culex pipiens pipiens (EO LC50 = 80.97 ppm, NEs LC50 = 48.27 ppm) and Plodia interpunctella (EO + β-cypermethrin LD50 = 0.16 μg larvae−1, NEs + β-cypermethrin LD50 = 0.07 μg larvae−1). Overall, our findings pointed out that NEs can increase twofold the insecticidal efficacy of EO, and thus, they can be considered further for the development of botanical insecticides.Fil: Jesser, Emiliano Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Zoología de Invertebrados II; ArgentinaFil: Lorenzetti, Anabela Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Yeguerman, Cristhian Alan. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Zoología de Invertebrados II; ArgentinaFil: Murray, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Domini, Claudia Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Werdin Gonzalez, Jorge Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Zoología de Invertebrados II; Argentin

Composition and biological activity of essential oils from Labiatae against Nezara viridula (Hemiptera: Pentatomidae) soybean pest

BACKGROUND: Plant essential oils have been recognised as an important natural source of insecticide. This study analysed the chemical constituents and bioactivity of essential oils that were isolated via hydrodistillation from Origanum vulgare L. (oregano) and Thymus vulgaris L. (thyme) against eggs, second instar and adults of Nezara viridula (L.). RESULTS: The major component of oregano was p-cymene, and, for thyme, thymol. The ovicidal activity was tested by topical application; the essential oil from thyme was more effective. The fumigant activity was evaluated in an enclosed chamber; the LC 50 values for oregano were 26.8 and 285.6 μg mL -1 for nymphs and adults respectively; for thyme they were 8.9 μg mL -1 for nymphs and 219.2 μg mL -1 for adults. To evaluate contact activity, a glass vial bioassay was used; the LC 50 values for oregano were 1.7 and 169.2 μg cm -2 for nymphs and adults respectively; for thyme they were 3.5 and 48.8 μg cm -2 respectively. The LT 50 analyses for contact and fumigant bioassays indicated that thyme was more toxic for nymphs and adults than oregano. Both oils produced repellency on nymphs and adults. CONCLUSION: These results showed that the essential oils from O. vulgare and T. vulgaris could be applicable to the management of N. viridula.Fil: Werdin Gonzalez, Jorge Omar. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Zoología de Invertebrados II; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Gutiérrez, María M.. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Zoología de Invertebrados II; ArgentinaFil: Murray, Ana Paula. Universidad Nacional del Sur. Departamento de Química. Instituto de Investigaciones en Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Ferrero, Adriana Alicia. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Zoología de Invertebrados II; Argentin