Olfactory behavioral responses of Oedaleus decorus asiaticus to three plant compounds

Author of the article:SHI Dan-Ni1, 2** KANG Peng1** CHANG Jing1 MA Chong-Yong3 GA Li-Wa3 HAN Li4 DAI Gui-Xiang5 LI Hai-Ping1***

Author's Workplace：1. College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot 010019, China; 2. Agricultural and Animal Husbandry Sciences Research Institute of Baotou City in Inner Mongolia Autonomous Region, Baotou 014000, China; 3. Forestry and Grassland Pest Control and Quarantine Station of Inner Mongolia Autonomous Region, Hohhot 010020, China; 4. Forestry and Grassland Protection Center of Hohhot City in Inner Mongolia Autonomous Region, Hohhot 010030, China; 5. Grassland Station of Ulanchap City in Inner Mongolia Autonomous Region, Jining 012000, China

Key Words：Stellera chamaejasme; Thymus mongolicus; azadirachtin; Oedaleus decorus asiaticus; olfactory behavioral response

Abstract：[Aim] To determine the effects of petroleum ether extracts from Stellera chamaejasme, Thymus mongolicus and azadiracthrin, on the behavioral responses of the 3rd instar Oedaleus decorus asiaticus larvae. [Methods] The leaf dish dipping method was used to test the antifeeding effect of plant extracts. Behavioral responses were measured using a Y-tube olfactometer and the leaf immersion method. Antennal responses of O. decorus asiaticus to plant extracts was measured with an electroantennogram (EAG). [Results] The median selective antifeedant concentrations (AFC50) of petroleum ether extracts from the roots of S. chamaejasme, T. mongolicus and azadirachtin were 0.461, 0.213 and 0.106 mg·mL-1, respectively after 48 h. In the Y-tube olfactometer, the repellence of thymol from T. mongolicus to adult O. decorus asiaticus was 86.67%, whereas the repellence of the aerial part, root, and entire S. chamaejasme plant, was 83.33%, 81.67%, and 80.00%, respectively. The repellence of plant compounds increased with concentration, exceeding 85% at the maximum tested concentration. The EAG responses of O. decorus asiaticus also increased with plant extract concentration. At 0.3 mg·mL⁻¹, the EAG value in response to thymol from T. mongolicus (0.67 mV) was higher than that of neochamaejasmine A and azadirachtin (both 0.33 mV). [Conclusion] Three plant extracts were sufficiently repellant to O. decorus asiaticus to have potential for development for use in the environmentally-friendly control of grassland locusts.