Insecticidal effect of Cymbopogon schoenanthus (L.) Spreng essential oil on adults of the rice weevil Sitophilus oryzae Linnaeus (Coleoptera: Dryophthoridae) in Togo

Fumigation, most often with phosphine, is commonly used to control pests in stored food and grain. This practice is highly toxic to animal, human, and environmental health. To find alternatives for the safe and healthy storage of grain, the insecticidal effects of the essential oil of Cymbopogon schoenanthus (L.), a grass native to Togo, were evaluated on adults of the rice weevil Sitophilus oryzae (L.). In vitro laboratory biological tests following the method recommended by the Insecticide Resistance Action Committee (IRAC) No. 1 Version 2, coupled with field tests (sorghum storage warehouse), demonstrated a highly significant insecticidal effect on rice weevil adults. C. schoenanthus essential oil at 0.5 ml. L-1 has an insecticidal effect on adult rice weevils in vitro and a repellent/insecticidal effect at 5 ml.L-1 diluted in soapy water and sprayed every 3 days for 30 days in farm stores to ensure sorghum quality and quantity. Safety assessment will be important for developing and integrated management strategy using this essential oil against this formidable pest.