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The aim of this report was to investigate the possible lethal effect of Thymus and Teucrium essential oils against insects. Antimicrobial activity was evaluated by the disc diffusion assay. Relative repellency, fumigation and plant lethality on certain pest species were tested. A higher concentration of thyme (9.95 µL/cm2) essential oil showed the greatest repellent effect against Tribolium confusum and Supella longipalpa. Exposure of pests to 2 µL thyme essential oil (EO) /l air resulted in 100 % mortality in 24 h. Thyme and Teucrium EO induced dose-response mortality of T. confusum larvae with LC50 values ⁣⁣of 45.22 and 38.10 µL/l air, respectively. Maximum lethality was recorded after 24 h and 48 h of exposure to the essence of T. algeriensis. Moreover, a total repellency effect was detected within 1 h of experiment at a concentration of 9.95 µL/cm2. Furthermore, complete lethality (100 %) of the nymph and adult of S. longipalpa (1˂ LT50 ˂6 h), T. confusum (LT50 ˂7 h) and the larvae of Blaps nefrauensis (1˂ LT50 ˂3 h) were observed. Additionally, thymol (0.3% w/w) was shown to induce moderate repellency and fumigant effect against studied insects. Overall, thyme and teucrium essential oils can be alternative botanical pesticides for these insects. But further experiments are needed to justify the insecticidal effect of essential oils used directly on T. confusum in cereal stores. As well, the experimental procedure using low doses of essential oil used for insecticidal potency should be repeated with high doses. [ABSTRACT FROM AUTHOR]

Aphids are serious pests of a wide range of agricultural crops, including pomegranates and grapevines. In addition, due to the negative environmental impacts of chemical insecticides, these pests are developing important resistance against aphicides. Therefore, one alternative method to control aphids is the use of essential oils (EO). The present study aimed to evaluate the insecticidal activity of Citrus aurantium and C. reticulata peel EO at different concentrations and with different exposure periods to pomegranate and grapevine aphids, Aphis punicae and A. illinoisensis via the topical application method under laboratory conditions. The results reveal that C. aurantium L. EO had greater toxicity against pomegranate and grapevine aphids, with LC50 of 0.37 and 0.82 μL/mL, respectively, at 48 h after application. The highest repellence effect was estimated for C. aurantium EO, at 2.5 μL/cm2, on A. punicae, with a value of 100% after an exposure time of 3 h, in contrast to the 88% repellence estimated for A. illinoisensis. The GC-MS investigation of both essential oils identified limonene, 3-carene, pinene, and p-cymene as active substances that could be attributed to the effects observed. Overall, our results offer a potential tool to control the two aphid species and could help in the development of integrated insect management in pomegranate and grapevine fields. [ABSTRACT FROM AUTHOR]