Chemical Composition and Evaluation of Insecticidal Activity of Subsp. and Subsp. Essential Oils Against Stored Products Pests

The problems of the environment and human health related to the use of synthetic and broad-spectrum insecticides have increasingly motivated scientific research on different alternatives and among these, the use of green systems, such as essential oils, have been explored. Several species of the Apiaceae and Asteraceae families, aromatic herbs rich in secondary bioactive metabolites, are used in the industrial field for pharmaceutical, cosmetic, and food purposes. Different essential oils extracted from some species of these families have shown acute toxicity and attractive and/or repellent effects towards different insects. In our work, we investigated the toxic potential of subsp. and subsp. essential oils against four insect species, , , , and which are common pests of stored products. The composition of both oils, extracted by hydrodistillation from the aerial parts of the two plants, was evaluated by GC×GC-MS. subsp. essential oil was rich in oxygenated sesquiterpenoids, such as cubebol (35.39%), 4--cubebol (22.99%), and cubenol (12.77%), while the subsp. essential oil was composed mainly of monoterpene hydrocarbons, such as -phellandrene (42.16%), limonene (23.87%), and -terpinene (11.80%). The toxicity Petri dish bioassays indicated that oil killed a mean of 65.50% of and 44.00% of adults, indicating a higher biocidal activity in comparison with oil, while toward the other species, no significant differences in mortality were recorded. oil could be, then, considered a promising candidate for further tests as an alternative biocide toward and . The possibility that the relatively high content of oxygenated sesquiterpenoids in essential oil determines its higher biocidal activity is discussed.