Insecticidal and acaricidal potency of essential oils against major pests in geothermal greenhouses

In southern Tunisia, geothermal greenhouses face major problems due to pest infestation, particularly Tuta absoluta, Bemisia tabaci and Tetranychus urticae. The efficacy of essential oils (EOs) from Artemisia campestris, Artemisia herba alba, Cleome arabica and Cymbopogon citratus was tested to develop sustainable integrated pest management. For this purpose, the oils were extracted, their volatile compounds were analyzed by GC-MS (gas chromatography and mass spectrometry) and their insecticidal and acaricidal activities against these three pests were evaluated in the laboratory. GC-MS analysis revealed the major compounds in each EO: Limonene, β-Pinene, and α-Pinene in A. campestris; Thujone and Myrtenyl acetate in A. herba alba; oxygenated monoterpenes, particularly trans-β-Terpineol, in C. arabica; and oxygenated monoterpenes, especially primarily 1-β-Citral, Citral, and Geraniol, in C. citratus. The results showed toxicity varied with pest species, essential oil concentration, and exposure time. The EOs showed insecticidal potential by direct contact with eggs, achieving a corrected mortality rate of over 48.97%, and by ingestion by second-stage T. absoluta caterpillars, with a corrected mortality rate of over 91.48%. They also demonstrated repellent activity against B. tabaci adults and contact acaricide activity against T. urticae eggs and adult females, with corrected mortality rates of over 88.88% and 81.81%, respectively. The EOs from these four plant species showed excellent efficacy as insecticides and acaricides, making them optimal sources for developing botanical pesticides against destructive pests.