Chemical composition of essential oils and solvent extracts of Artemisia scoparia, Seriphidium brevifolium, and Salvia yangii and their comparative fumigant toxicity against stored-grain pests Tribolium castaneum and Sitophilus oryzae /

Abstract

Tribolium castaneum and Sitophilus oryzae are listed among the most destructive pests of stored grains. Although synthetic insecticides and fumigants are commonly employed for their control, plant-based formulations offer safer, and eco-friendly alternatives. The aim of the current study was to explore the insecticidal potential of three aromatic plants against stored grain pests. Artemisia scoparia, Seriphidium brevifolium, and Salvia yangii were extracted using steam distillation and macerated in hexane and methanol, and their chemical compositions were investigated using gas chromatography-mass spectrometry. The insecticidal activity of plant essential oils (EOs) and solvent extracts was evaluated against laboratory-reared T. castaneum and S. oryzae using a fumigation bioassay. A. scoparia EO showed the highest insecticidal activity with LC50 of 7.4 mg/L and 5.3 mg/L against T. castaneum and S. oryzae, respectively, after 12 h exposure. The LC50 of S. brevifolium was 21.1 mg/L and 2.9 mg/L against T. castaneum and S. oryzae, respectively, after 12 h exposure. Compared to their respective EOs, plant solvent extracts exhibited lower bioactivity; however, the methanolic extract of S. brevifolium showed notable insecticidal activity against T. castaneum and S. oryzae. The major constituents found in A. scoparia EO were capillene (38.3%), γ-terpinene (19.3%), and β-myrcene (17.2%). The EO of S. brevifolium comprised camphor (31.6%), eucalyptol (29.3%), and thujone (9.9%). EOs and methanolic extracts of A. scoparia and S. brevifolium demonstrated the highest fumigant toxicity against T. castaneum and S. oryzae, highlighting their potential as botanical pest control agents to protect stored grains