Browsing by Author "Caballero Gallardo, Karina"

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    Chemical composition and bioactivity of Piper auritum and P. multiplinervium essential oils against the red flour beetle, Tribolium castaneum (Herbst)
    (2014) Caballero Gallardo, Karina; Olivero Vebel, Jesús; Pino Benítez, Nayive; Stashenko, Elena E.
    Stored grain insects have shown resistance to synthetic insecticides, fact that has promoted the use of vegetable species for integrated pest management. Piper auritum and P. multiplinervium are two plants from the Piperaceae family present in the department of Chocó, Colombia, one of the most important hot spots of biodiversity in the world. This study was conducted to determine the repellent activity and toxicity of essential oils (EOs) isolated from these plants against Tribolium castaneum, using the area preference and contact toxicity methods, respectively. P. auritum EO presented greater repellency than P. multiplinervium, the first showed 100% lethality at minimum tested exposure period (24 h) whereas the second reached 16% at 72 h. EOs were analyzed by gas chromatography-mass spectrometry. P. auritum major components were safrole (93.2%) and miristicine (4.3%), whereas for P. multiplinervium were β-elemene (9.0%), trans-β- caryophyllene (5.3%) and caryophyllene oxide (4.1%). It is speculated that the repellent effect of P. auritum may be related to its safrole content, a known repellent. These results evidenced Piper species could be used for development of repellents against T. castaneum.
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    Essential oils from plants of the genus Cymbopogon as natural insecticides to control stored product pests
    (2015-04) Hernandez Lambraño, Ricardo; Pájaro Castro, Nerlis; Caballero Gallardo, Karina; Stashenko, Elena E.; Olivero Vebel, Jesús
    The repellent and fumigant activities of essential oils (EOs) isolated from plants of the Cymbopogon genus against adults of Oryzaephilus surinamensis (L.) and Sitophilus zeamais Motsch were investigated. Cymbopogon martinii was the most toxic EO with LC50 values of 37.2 and 159 mL/L air for O. surinamensis and S. zeamais, respectively. Cymbopogon nardus EO showed greatest repellent activity with RC50 values of 0.03 and 0.04 mL/cm2, respectively, for examined pests. All oils were more effective as repellents than the commercial product IR3535, and O. surinamensis was more sensitive than S. zeamais to the EOs. These results suggest that EOs isolated from plants of the genus Cymbopogon can play an important role in stored grain protection and reduce the risks associated with the use of synthetic insecticides.
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    Plants cultivated in Choco, Colombia, as source of repellents against Tribolium castaneum (Herbst)
    (2014-07) Caballero Gallardo, Karina; Pino Benítez, Nayive; Pájaro Castro, Nerlis; Stashenko, Elena E.; Olivero Vebel, Jesús
    Essential oils (EOs) of eight plants collected in Choco, Colombia, including Piper divaricatum, P. pseudolanceifolium, P. confertinodum, P. diazanum, Ocimum campechianum, Siparuna conica, Mikania micrantha and Hedychium coronarium, were analyzed by gas chromatography–mass spectrometry and tested as repellents against Tribolium castaneum, using the area preference method, after 2 and 4 h exposure. The main components found in Eos were methyl eugenol, trans-β-cariophyllene, methyl eugenol, α-pinene, δ-cadinene, γ-elemene, α-pinene and 1,8-cineol, for O. campechianum, P. pseudolanceifolium, P. divaricatum, P. confertinodum, P. diazanum, S. conica, M. micrantha, and H. coronarium, respectively. Best repellent activities were observed for oils from O. campechianum and P. pseudolanceifolium with mean repellent concentration (RC50) values of 0.00006 and 0.0001 μL/cm2 after 2 h, and 0.00003 and 0.0001 μL/cm2 after 4 h, respectively; whereas the least potent was that from M. micrantha, with RC50 values of 0.074 and 0.040 μL/cm2 at 2 and 4 h exposure times, respectively. Based on average percentage repellence, oils from P. pseudolanceifolium and O. campechianum were classified as Class IV repellents and were better than the commercial repellent IR3535, classified as Class II. These data evidence the Choco region as an important source of natural repellents with promising commercial opportunities.