Insecticidal Activity of Essential Oils and Their Synergistic Effect on Improving the Efficacy of β-Cypermethrin against .

We screened the contact activity of 32 commercial essential oils (EOs) and their synergistic effect with β-cypermethrin against . Results showed that the most effective EOs against were from , , and , with LD values of less than 500 μg/insect. The most potent synergistic effects of β-cypermethrin on were from and .