Fumigant Toxicity and Oviposition Deterrency of the Essential Oil from Cardamom, Elettaria cardamomum, Against Three Stored—product Insects

Use of insecticides can have disruptive effects on the environment. Replacing the chemical compounds in these insecticides with plant materials, however, can be a safe method with low environmental risk. In the current study, chemical composition and insecticidal activities of the essential oil from cardamom, Elettaria cardamomum L. (Maton) (Zingiberales: Zingiberaceae) on the adults of three stored product pests was investigated. Results indicated that essential oil of E. cardamomum toxic to the bruchid beetle, Callosobruchus maculatus Fabricius (Coleoptera: Bruchidae), the red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), and the flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). Adults of E. kuehniella were more sensitive than the Coleoptera. Also, the highest mortality of these insects was seen after 12 hours. Results of the LT50 tests showed that the lethal time of mortality occurred between 10–20 hours in various test concentrations. Essential oil of E. cardamomum had a good efficacy on oviposition deterrence of C. maculatus females, too. The chemical constituents of the essential oils were analyzed by gas chromatography—mass spectrometry. The major constituents of cardamom were identified as 1,8-cineol, α-terpinyl acetate, terpinene and fenchyl alcohol. These results suggest that essential oil of E. cardamomum is a good choice for control of stored product pests

Toxicity of citrus essential oils against Ceratitis capitata (Diptera: Tephritidae) larvae

Citrus peel essential oils are considered to constitute the most important resistance factor of citrus fruits against fruit flies. Essential oils were obtained from three sweet orange varieties, one bitter orange and one lemon variety. Yield, chemical composition and toxicity against neonates of the Mediterranean fruit fly were determined. Based on chemical analysis, the toxicity of commercially purchased major and minor components (monoterpenes and sesquiterpenes) of essential oils was determined. In addition, fractions were prepared to evaluate the role of minor components in the toxicity of crude essential oils. Limonene was by far the most abundant ingredient (96.2-97.4%) in all sweet orange varieties and in bitter orange, while the concentration of limonene was much lower in lemon essential oils (74.3%). Orange and bitter orange essential oils were more toxic than lemon essential oils. The toxicity of orange and bitter orange essential oils was similar to that of their major component limonene. In tests of commercially purchased chemicals, the oxygenated components of essential oils were more toxic than hydrocarbons but their low concentration in citrus essential oils could not affect the toxic activity of essential oils. The presence of alpha-pinene and beta-pinene seems to account for the lower toxicity of lemon essential oils in relation to other citrus essential oils. The importance of understanding the toxicity of essential oils in relation to their composition and their role regarding the resistance of citrus fruits to Ceratitis capitata infestation is discussed