A Study On The Host-specificity Of The Alien Leafbeetle, Ophraella Communa Lesage (Coleoptera: Chrysomelidae) In China, Mainland

The ragweed Ambrosia artemisiifolia, an alien invasive weed, can profoundly influence natural ecosystems, agriculture, and human health. Recently an exotic leafbeetle, Ophraella communa (Coleoptera: Chrysomelidae: Galerucinae) was reported in mainland China heavily defoliating A. artemisiifolia. However, it would not be regarded as a safe biological control agent for control of the ragweed before it satisfies the requirement of the risk assessment. The host-specificity test is central to the risk assessment in the practice of classical biological control of weeds. The objective of this study is to assess potential ecological risks of O. communa by host-specificity testing and relevant experiments.1. Host plant choice-tests on Ophraella communaChoice-test experiments in the laboratory were caaried out to determine the host plants fed by O. communa larvae and adults among 52 plants, including wild plant, flower, and vegetables close to the ragweed A. artemisiifolia in Compositae, grain crops, and vegetables. Results showed that larvae inflicted, to some extent, feeding damages to Composite plants including Eupatorium adenophorum, Carpesium abrotanoides , Helianthus annuus, Xanthium sibiricum, and Centipeda minima. Adults performed feeding on H. annuus, H. tuberosus, X.sibiricum, and C. abrotanoides.2. Experiments on host suitability for Ophraella communa on different test plantsBased on results of choice tests carried out, the plants fed by the leafbeetle were observed as hosts for survival, development, and reproduction of O. communa larvae in the lab and field. In the lab larval and pupal development time were observed on excised leaves. In the field development and reproduction performances were studied on potted test plants from neonate larvae. Results indicated that O. communa neonate larvae could develop into adults by feeding on X. sibiricum, H. tuberosus, and most varieties of sunflower H, annuus even though survival on these plants was much lower than on the target weed A. artemisiifolia. Moreover, eggs, laid by adults fed on X. sibiricum and some varieties of the...