The effects of non-host plant extracts on electroantennogram responses, behavior and egg hatching of codling moth, Cydia pomonella

The codling moth ( Cydia pomonella L.) is a significant pest of pome fruit throughout the world. Behavioral and ovicidal activities of five non-host plant extracts ( Arctium lappa , Bifora radians , Humulus lupulus , Verbascum songaricum , Xanthium strumarium ), synthetic sex pheromone, ( E , E )-8,10-dodecadienol (codlemone), and the plant volatile lure, (2 E ,4 Z )-2,4-decadienoate (pear ester) were evaluated against the codling moth, C. pomonella L. Codlemone elicited the greatest electroantennogram (EAG) response (6.2 ± 1.2 mV) of the compounds tested from male C. pomonella while pear ester elicited 1.7 ± 0.1 mV EAG response in female moths. Codlemone attracted 34.5% of male C. pomonella in olfactometer studies, and it was followed by the X. strumarium extract with 24.8%. There was a significant difference between the behavior of unmated and mated females. V. songaricum extract was the most active extract, attracting 25.4% of unmated females. However, mated C. pomonella females exhibited greatest attraction to pear ester. In a wind tunnel bioassay, combining X. strumarium with codlemone significantly increased the response of male upwind flight and source contact as compared with codlemone alone. All plant extracts, except for V. songaricum , significantly reduced the number of eggs laid. The plant extracts exhibited some toxic effects to eggs, and hatching rate of eggs was reduced as compared with the control. Our results indicate that some of the plant extracts tested are potential candidates for practical use after elucidation and characterization of active compound(s).