Chemical Composition and Bioinsecticidal Effects of <i>Thymus zygis</i> L., <i>Salvia officinalis</i> L. and <i>Mentha suaveolens</i> Ehrh. Essential Oils on Medfly <i>Ceratitis capitata</i> and Tomato Leaf Miner <i>Tuta absoluta</i>

The present work was aimed to study the toxicity of the essential oils of three aromatic and medicinal plants on the tomato leaf miner <i>Tuta absoluta</i> and the Medfly <i>Ceratitis capitata</i> as an alternative to conventional pesticides. We carried out a phytochemical and insecticide study of <i>T. zygis</i> L., <i>S. officinalis</i> L. and <i>M. suaveolens</i> Ehrh. essential oils (EOs) through the study of their chemical composition and their toxicity on <i>C. capitata</i> adults and <i>T. absoluta</i> larvae. The extraction of the EOs by hydrodistillation showed yields of 3.87 ± 0.03, 4.09 ± 0.23 and 4.35 ± 0.11 for <i>T. zygis</i>, <i>S. officinalis</i> L. and <i>M. suaveolens</i> Ehrh., respectively. The identification of the chemical composition of the EOs by GC/MS showed that oxygenated monoterpenes constituted the most abundant group for all the extracted EOs. The major compounds were rather diversified depending on plant species. In fact, the <i>S. officinalis</i> L. EO mainly contained trans-thujone (21.80 %), the <i>M. suaveolens</i> Ehrh. EO mainly contained piperitenone oxide (71.19%), and carvacrol (61.60%) was the main component of the <i>T. zygis</i> L. EO. An insecticidal effect was observed for the three studied EOs on <i>C. capitata</i> adults and <i>T. absoluta</i> larvae. The observed LD₅₀ values were 0.80 µL/mL and 11.04 µL/mL for <i>M. suaveolens</i> and <i>S. officinalis</i>, respectively, on <i>T. absoluta</i> larvae. For <i>C. capitata</i> adults, the obtained LD₅₀ values were 0.9 µL/mL and 11.78 µL/mL for <i>M. suaveolens</i> and <i>T. zygis</i>, respectively. The presented findings could contribute to the development of biopesticides for plants as a component of integrated pest management strategies in citrus and tomato crops.