Insecticidal potential of essential oil from the leaves of Citrus aurantium L. against Oryzaephilus surinamensis (F.), Lasioderma serricorne (L.) and Sitophilus oryzae (L.)

Abstract

In search for alternatives of conventional pesticides, plant essential oils have been widely investigated. Essential oils from aromatic plants are recognized as proper alternatives to chemical fumigants. In this research fumigant toxicity, repellent activity and persistency of Citrus leaves Citrus aurantium L. essential oil were tested against three stored product pests, the sawtoothed grain beetle, Oryzaephilus surinamensis (F.), cigarette beetle Lasioderma serricorne (L.) and the rice weevil, Sitophilus oryzae (L.). The essential oils were extracted from citrus dried leaves by Clevenger-type distiller. The Watman filter paper No: 1 was used for fumigant toxicity in 40 ml glass vial. Repellency effect of the essential oil was evaluated by comparing the number of adults in both treated and untreated portions. Results showed that the mortality increased with increasing concentration. The LC50 values were 64.94, 202.49 and 364.25 and the LC90 were 144.94, 659.29 and 663.05 µl/l air respectively. Toxicity of oil against O. surinamensis was higher than two others pest. The highest and lowest repellency effects of four concentrations (0.1, 0.2, 0.41 and 0.83 µl/cm2) were 96.6% and 73.33% for O. surinamensis and L. serricorne respectively. Based on repellency percentage, average repellency is grades V, IV and IV respectively of the sextet classification. Persistency was different depending on concentration and species insects. The results have shown that the fumigant toxicity of C. aurantium on these stored pest were remarkable, therefore this oil could be a safer fumigant to control these pests than those currently used.