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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 <i>Calendula incana</i> subsp. <i>maritima</i> and <i>Laserpitium siler</i> subsp. <i>siculum</i> essential oils against four insect species, <i>Sitophilus oryzae</i>, <i>Lasioderma serricorne</i>, <i>Necrobia rufipes</i>, and <i>Rhyzoperta dominica,</i> 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. <i>Calendula incana</i> subsp. <i>maritima</i> essential oil was rich in oxygenated sesquiterpenoids, such as cubebol (35.39%), 4-<i>epi</i>-cubebol (22.99%), and cubenol (12.77%), while the <i>Laserpitium siler</i> subsp. <i>siculum</i> essential oil was composed mainly of monoterpene hydrocarbons, such as <i>β</i>-phellandrene (42.16%), limonene (23.87%), and <i>β</i>-terpinene (11.80%). The toxicity Petri dish bioassays indicated that <i>C. maritima</i> oil killed a mean of 65.50% of <i>S. oryzae</i> and 44.00% of <i>R. dominica</i> adults, indicating a higher biocidal activity in comparison with <i>L. siculum</i> oil, while toward the other species, no significant differences in mortality were recorded. <i>Calendula maritima</i> oil could be, then, considered a promising candidate for further tests as an alternative biocide toward <i>S. oryzae</i> and <i>R. dominica</i>. The possibility that the relatively high content of oxygenated sesquiterpenoids in <i>C. maritima</i> essential oil determines its higher biocidal activity is discussed.