Behavioural and insecticidal activity of Salvia officinalis L. (Lamiaceae) essential oil against Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) and Rhyzopertha dominica Fabricius (Coleoptera: Bostrichidae)

The insecticidal and behavioural effects of Salvia spp. on stored product pests has been known for a long period. The aim of this work is to investigate the efficacy of essential oil obtained from sage [Salvia officinalis L. (Lamiaceae)] as repellent and contact toxicity against two important stored grain insects Tribolium confusum Jacquelin du Val (Col: Tenebrionidae) and Rhyzopertha dominica (Fabricius) (Col: Bostrichidae) under laboratory conditions. In the repellent activity test, four concentrations were used (0.047 μl/cm2, 0.118 μl/cm2, 0.236 μl/cm2 and 0.590 μl/cm2) and the experiments were carried out on glass petri dishes. In contact activity tests, essential oil solutions prepared at a concentration of 10% (v/v) were applied to insects with a hand-operated microapplicator at 0.1 μl/insect dose and dead individuals were recorded after 24 hours. The highest repellent activity was seen against R. dominica at 53.33%, at 0.118 μl/cm2 concentration after half an hour, compared with a rate of 36.67% at 1/2 hour of 0.118 μl/cm2 dose in T. confusum. In contact toxicity studies, 91.02% mortality was found for R. dominica, while for T. confusum this mortality was 33.67%. The results of this study show that essential oils of S. officinalis have significant contact toxicity on adults of R. dominica