Abstract Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) is one of the main stored grain pests in the world. The present study describes the investigation of the insecticidal activity of essential oils (EOs) extracted from the leaves of twelve Myrtaceae species against this important pest. The essential oils of Eucalyptus resinifera Sm. (Myrtaceae) were the most actives and presented 1,8-cineole (59.3%), p-cymene (12.9%), and α-pinene (9.7%) as the main components. Contact bioassays revealed that the EOs of E. resinifera were less toxic (LD50 = 17.08 μg mg−1 of insect body weight; LD95 = 56.17 μg mg−1) than the commercial insecticide pirimiphos-methyl (LD50 = 0.49 μg mg−1; LD95 = 1.14 μg mg−1) used as positive control. In the fumigation bioassays, however, these EOs were more effective (LC50 = 70.55 μL L−1, LC95 = 266.40 μL L−1) than the commercial insecticide (LC50 = 154.74 μL L−1; LC95 = 334.95 μL L−1). The LT50 on R. dominica adults for the EOs of E. resinifera were 1.75 h and 13.0 h in the contact and fumigation bioassays, respectively. The fumigant effect was due to the terpenoid 1,8-cineole, while the contact effect was caused by the association of the major components of the essential oils of E. resinifera. Thus, the EOs of E. resinifera have potential to be used as an alternative to commercial insecticides in R. dominica management.

中文翻译：

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桃金娘科植物精油的化学多样性及其对多米尼克根霉的杀虫活性

摘要 Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) 是世界上主要的储粮害虫之一。本研究描述了从十二种桃金娘科物种的叶子中提取的精油 (EO) 对这种重要害虫的杀虫活性的调查。Eucalyptus resinifera Sm 的精油。（桃金娘科）活性最高，主要成分为 1,8-桉树脑（59.3%）、对伞花烃（12.9%）和α-蒎烯（9.7%）。接触生物测定表明，E.resinifera 的 EO 毒性（LD50 = 17.08 μg mg-1 昆虫体重；LD95 = 56.17 μg mg-1）比商业杀虫剂甲基嘧啶磷（LD50 = 0.49 μg mg-1； LD95 = 1.14 μg mg-1) 作为阳性对照。然而，在熏蒸生物测定中，这些 EO 更有效（LC50 = 70.55 μL L-1，LC95 = 266。40 μL L-1）比商业杀虫剂（LC50 = 154.74 μL L-1；LC95 = 334.95 μL L-1）。在接触和熏蒸生物测定中，R. dominica 成虫对 E.resinifera EOs 的 LT50 分别为 1.75 小时和 13.0 小时。熏蒸效果是由于萜类化合物 1,8-桉树脑，而接触效果是由 E.resinifera 精油的主要成分的结合引起的。因此，E. resinifera 的 EOs 有可能在 R. dominica 管理中用作商业杀虫剂的替代品。而接触效应是由 E.resinifera 精油主要成分的结合引起的。因此，E. resinifera 的 EOs 有可能在 R. dominica 管理中用作商业杀虫剂的替代品。而接触效应是由 E.resinifera 精油主要成分的结合引起的。因此，E. resinifera 的 EOs 有可能在 R. dominica 管理中用作商业杀虫剂的替代品。