Conflict of interest

control. These halves were joined, and a fixed number of insects were released on the center. Observations on the number of insects present on both the treated and untreated halves were recorded after 2 and after 4 h. The highest repellent activity

(2 h) and 92% 3 (4 h) were observed, which were higher than those obtained for a commercial repellent at the same concentration and exposure times (78% 5 and

Weevils that consume flour (Tribolium castaneum), peanuts and wheat bread (Ulomoides dermestoides) merit attention alongside other insects of major concern in crop production and storage of cereals and other products. Alcala and co-workers [85] used the area preference method to show that EOs of Elettaria cardamomum, Salvia officinalis and L. origanoides (carvacrol chemotype) had repellent action against both pest insects, while the repellency in the controls was null. This repellency increased when the EO concentrations were higher. None of the EOs

presented attractant action for either of the exposure times. A 100% repellency was obtained at the highest concentration tested (1.6% v/v), except for S. officinalis against U. dermestoides at 2 h of treatment that had a 97% of repellency. Mean repellent concentration (RC50) values showed that E. cardamomum, S. officinalis, and L. origanoides had better repellent properties against U. dermestoides than a commercial preparation that contained 15% of ethyl butylacetylaminopropionate. The carvacrol-rich chemotype of L. origanoides was the most potent, with RC50

Several tropical diseases for which there is no vaccine yet (yellow fever, Zika fever, chikungunya, dengue) are transmitted by Aedes aegypti. The strategies to prevent these illnesses involve the use of insecticide or repellent agents. Since several pesticides have deleterious environmental effects and affect humans, there is a strong interest in finding EOs and plant extracts that can be effective in controlling Aedes aegypti. The guideline that good larvicide candidates are substances with LC50 < 100 mg/L [86] shows the importance of the finding that the EOs from L. origanoides (LC50 = 54 mg/L) and Swinglea glutinosa (LC50 = 66 mg/L) had an improved performance when used as a mixture (LC50 = 38 mg/L). Other EO

values of 0.220 and 0.207% (v/v), for T. castaneum and U. dermestoides,

binary mixtures showed similarly interesting activity (Turnera diffusa and S. glutinosa, LC50 = 64 mg/L; L. alba and S. glutinosa, LC50 = 49 mg/L) [87].

products that employ them as active ingredients.

Colombia's geographic and botanical conditions favor the development of its EOs agroindustry to convert this country into an important provider to the evergrowing EO world market. The initial offer will consist of EOs from aromatic plants of European and Asian origins, which are well-known and commonly traded in the international market. However, the results from the very small survey of Colombia's biodiversity indicate that there are many promising alternatives for future market expansion. The evaluation of biological activities of EOs obtained from plants growing in Colombia points toward many opportunities to develop a wide range of

Financial support from Patrimonio Autónomo, Fondo Nacional de Financiamiento para la Ciencia, Francisco José de Caldas, grants RC-432-2004, RC-0572-2012, and

. Repellence values of 86% 5

was observed at an EO concentration of 0.2 μL/cm<sup>2</sup>

76% 9, respectively).

Essential Oils - Oils of Nature

respectively.

5. Conclusions

Acknowledgements

138

The authors declare that they do not have conflict of interest.
