Vol. 5, Issue 1, Part B (2023)

The aim of this study was to verify the degree of repellent effect of two chemical substances (DEET and 2-undecanone) and three essential oils (EOs), Allium sativum, Lavandula angustifolia and Eucalyptus globulus. Leptinotarsa decemlineata Say. Were exposed to different concentrations (0.2, 0.4 and 0.6%) in a two-choice olfactometer and (0.02, 0.04 and 0.06 ml/cm²) area preference assay. The effect was recorded 15 minutes, in olfactometer and 6-24 hours in area preference test, after the application of the treatments. It was found that A. sativum, E. globulus, and L. angustifolia had a significant repellent effect. We also found that the repellent effect increased with increasing concentration and time. An olfactometer and area preference assay achieved the highest repellency index (%) from (A. sativum, E. globulus, L. angustifolia, deet, and 2-undecanone), indicating RI 80% (15 mins) and RI 93% at 6-24 hours in concentration (0.6%, 0.06 ml/cm²). The present results show that the tested oils have high activity against L. decemlineata. We concluded that the EOs may have potential as an alternative to chemical control, all these efficient EOs could be used as effective biocontrol agents against various field pests.