author(s)
Hayette Bouzeraa, Bessila-Bouzeraa M, Labed N, Sedira F and Ramdani L

abstract
In the present study, the efficiency of the insecticidal activity of Artemisia herba alba essential oil was evaluated on two insect pests of stored food, Plodia interpunctella and Ephestia kuehniella. Different concentrations of the oil were tested on the last instar larvae for repellent activity (25, 75, 100, 120, 130 and 150µl/ml ethanol for both insect) and fumigant toxicity bioassay (50, 75, 100 and 120 µl/l air for P. interpunctella and 50, 150, 180, 200 and 600 µl/l air for E. kuehniella) under laboratory conditions. Results showed repellent activity of the oil against both insect with stronger effect on P. interpunctella larvae. The oil caused toxicity in both insect larvae. Median lethal concentrations of the oil (LC₅₀) recorded against P. interpunctella larvae were 162.1, 144.9 and 141.1 µl/l air at 24, 48 and 72h after exposure. LC₅₀ values of this oil against the larvae of E. kuehniella were 901.1, 782.4 and 514.2 µl/l air after exposure at the same times, respectively. According to the results, the oil had a stronger activity on P. interpunctella, whereas, E. kuehniella was the most tolerant to the oil activity. These results would lead to a prior knowledge in the specificity of essential oils toward different insect orders and confirm the efficiency of essential oils in the control of insect pests of stored product.