Insecticidal, Fumigant, and Repellent Activities of Sweet Wormwood Oil and Its Individual Components Against Red Imported Fire Ant Workers (Hymenoptera: Formicidae)

In total, 29 compounds from sweet wormwood (Artemisia annua L.) oil were identified using gas chromatography-mass spectrometry. The five active components were D-camphor, linalool, cineole, α-terpineol, and L(-)-borneol. The effectiveness of A. annua oil, as well as d-camphor, linalool, cineole, α-terpineol, and L(-)-borneol, as fumigants, contact insecticides, and repellents, were tested on the red imported fire ant Solenopsis invicta Buren. The results indicated that A. annua oil has no significant topical toxicity; however, the spray contact test revealed that it has strong insecticidal activity and the inhibitory effect is stronger during closed exposure than during open exposure. In the fumigant test, cineole and D-camphor exhibited strong fumigant toxicity on minor and major S. invicta workers. They also caused 100% mortality at 5, 3, 2, and 1 mg/centrifuge tube but not at 0.5 mg/centrifuge tube. The mortality rates of linalool, α-terpineol, and L(-)-borneol exceeded 80% at 5, 3, and 2 mg/centrifuge tube. In the repellent test, cineole and d-camphor showed significant repellency at 100, 10, and 1 mg/kg. However, linalool, α-terpineol, and L(-)-borneol significantly facilitated digging at 10 and 1 mg/kg.