Chemical compositions and insecticidal activities of Clausena lenis (Rutaceae) and Clausena excavata (Rutaceae) essential oils against two stored-product insects

Abstract

Tribolium castaneum Herbst, 1797 (Coleoptera: Tenebrionidae) and Lasioderma serricorne Fabricius, 1792 (Coleoptera: Anobiidae) are two globally prevalent stored-product pests. Traditional management strategies primarily involve the use of synthetic insecticides and repellents. However, plant essential oils (EOs) pose lower risks to human health and ecological environment. This study focused on two Clausena species plants, Clausena lenis and Clausena excavata, exploring the insecticidal and repellent properties of EOs extracted from different parts of them against T. castaneum and L. serricorne. The EOs were extracted via hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC–MS). A total of 57 components were identified. The EOs from the branches and leaves of two Clausena plants were primarily composed of sesquiterpenes, while C. lenis fruits EO was mainly composed of monoterpenes (58.79 %) and esters (38.95 %). Clausena lenis leaves EO demonstrated the highest contact toxicity against T. castaneum, with a mortality rate of 72 % at a concentration of 50 %, while C. lenis branches EO was particularly effective against L. serricorne, with an LD₅₀ of 8.24 mg/L air. In addition, C. lenis fruits EO exhibited the best repellent effect against these two pests. According to these results, C. lenis and C. excavata show promise to be developed into eco-friendly botanical insecticides for the prevention and control of stored-product pests, especially for application in agricultural storage. These findings highlight the potential for these EOs to serve as sustainable alternatives to synthetic insecticides, offering a safer and environmentally friendly approach to pest management in stored agricultural products.