Insecticidal Activity of Essential Oil from Seeds of Foeniculum vulgare (Apiales: Apiaceae) Against Sitophilus zeamais (Coleoptera: Curculionidae) and Its Effects on Crop Seed Germination

Abstract Many aromatic herbs in the family Apiaceae produce essential oils that are used on an industrial scale for medicinal, cosmetic, and food purposes. Essential oils from plants that show insecticidal activity can be substituted for synthetic insecticides to reduce environmental pollution or harmful toxicity to humans. Insecticidal activity of essential oil from seeds of coriander, Foeniculum vulgare Miller (Apiales: Apiaceae), on maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), and its effects on seed germination of three major economic crops were investigated. Essential oil from F. vulgare seeds was analyzed by gas chromatography–mass spectrometry and found to contain 25 components, with anethole (43.78%) as the main constituent. Other basic compounds were estragole (28.33%), fenchone (16.68%), d-limonene (2.62%), alpha-pinene (1.84%), and p-cymene (1.28%). Foeniculum vulgare essential oil was toxic to maize weevil when used as a fumigant with a median lethal concentration at 48 h of 10.42 µL/L air. A concentration of 64 µL/L air was most effective, killing 100% of maize weevil within 24 h. The repellent effect on maize weevil increased to 75% at 24 h at a concentration of 16 µL/L air. Rice (Oryza sativa L.) and sorghum (Sorghum bicolor [L.] Moench) seeds fumigated with 32 µL/L air of F. vulgare essential oil exhibited a slight decrease in germination rate (germination >90%). Our results indicate that essential oil from F. vulgare seeds have potential for application in the management of maize weevil in stored products.