Antifeedant and repellent effects of root extracts of some aromatic plants against bean weevil Acanthoscelides obtectus Say (Coleoptera: Bruchidae)
Plant root extracts in methanol, chloroform and hexane of three widely distributed plants were evaluated for their feeding deterrency and repellency to Acanthoscelides obtectus Say. The plant species studied were, ginger-Zingiber officinale Roscoe (Zingiberaceae), garden radish-Raphanus sativus L. var. sativus (Brassicaceae) and black carrot-Daucus carota L. spp. sativus var. atrorubens Alef. (Apiaceae). Antifeedant potential of these root extracts was determined by the deterrence or antifeedant test using bean wafer disks. The total coefficient of deterrence (T) was determined for each root extract. Repellency tests were performed using filter-paper circles cut in halves. The root extracts were applied on each half at a concentration of 0.36 mg.cm-2. Percentual repellency (PR) was determined for each root extract. The chloroform root extracts of Z. officinale had the strongest antifeedant effect (class ++++) followed by the methanol root extracts (class ++++) and hexane root extracts of the same species (class +++). Root extracts of Z. officinale had stronger antifeedant effect than R. sativus var. sativus and D. carota spp. sativus var. atrorubens root extracts. A moderate repellent effect of R. sativus var. sativus and Z. officinale root extracts on A. obtectus was was observed, the hexane root extracts of R. sativus var. sativus was the one with strongest repellency (class 4). Among the root extracts analysed, the strongest antifeedant effect occur with the chloroform root extracts of Z. officinale and the hexane root extracts of R. sativus var. sativus showed the strongest repellency effect.
Mehmet Karakas. Antifeedant and repellent effects of root extracts of some aromatic plants against bean weevil Acanthoscelides obtectus Say (Coleoptera: Bruchidae). International Journal of Entomology Research, Volume 5, Issue 2, 2020, Pages 33-37