Combined action of Lavandula angustifolia Miller essential oil and gamma irradiation treatment on some biological aspects of the Mediterranean flour moth Ephestia kuehniella (Zeller)

This study evaluated the effectiveness of an integrated pest management intervention for controlling the Mediterranean flour moth Ephestia kuehniella Zeller using gamma radiation and Lavandula angustifolia Moench essential oil as feasible alternatives to synthetic insecticides. The mortality rate of E. kuehniella larvae treated with either gamma radiation or L. angustifolia essential oil separately was much lower than the mortality rate after the combined treatment. High synergistic effects (Synergism = 0.1) were observed in all dosages, especially using 1.14 and 1.7 mu L/L air of L. angustifolia in combination with 200 Gy of gamma radiation, which was more effective than the other treatments. The results of the antifeedant test indicated that the relative growth rate and relative consumption rate in fumigated (0.021 and 0.021 mg/mg/day) and irradiated (0.026 and 0.049 mg/mg/day) larvae were significantly lower than those of non-treated ones (0.035 and 0.093 mg/mg/day). The results also showed a significant increase in the efficacy of conversion of ingested food and feeding deterrent index due to both irradiation and essential oil. The experiments showed that the known insecticidal effectiveness of essential oils can be enhanced by preliminary irradiation.