Olfactory and Feeding Preferences of Cryptorhynchus lapathi L. (Coleoptera: Curculionidae) Among Hybrid Clones and Natural Poplars

Hybrid poplar clones show varying levels of attack by Cryptorhynchus lapathi (L.), a wood-boring weevil. We studied differences in olfactory and feeding behavior among four different hybrid poplars in a series of laboratory bioassays. Weevils did not discriminate between resistant and susceptible clones based on olfaction in pitfall bioassays or antennal responses but did discriminate against the most resistant hybrid, NM 6 (P. nigra L. × P. maximowiczii Henry), in choice and no-choice paired-twig feeding bioassays. In addition, the susceptible hybrid, TN 302–9 (P. trichocarpa Torrey and Gray × P. nigra), was preferred for feeding over Salix scouleriana Barratt ex Hooker, a preferred host in the wild. We conclude that resistance among hybrid poplars is in part based on antixenotic cues before oviposition.