Location: Systematic Entomology LaboratoryTitle: Host range validation, molecular identification, and release and establishment of a Chinese biotype of the Asian leaf beetle Lilioceris cheni Gressitt & Kimoto) Author
|Konstantinov, Alexander - Alex|
Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/26/2013
Publication Date: 7/17/2013
Citation: Center, T.D., Min, R., Dray, F.A., Rohrig, E., Purcell, M., Konstantinov, A.S. 2013. Host range validation, molecular identification, and release and establishment of a Chinese biotype of the Asian leaf beetle Lilioceris cheni Gressitt & Kimoto. Biocontrol Science and Technology. 23(7):735-755. Interpretive Summary: Leaf beetles are among the most important insects for U.S. Agriculture. Many are serious pests, feeding on crops and destroying valuable plants; others are important biological control agents that can be used to control unwanted weeds. This work provides information on air potato (an invasive weed of Asian origin) and its leaf beetle biological control agents. This study will be useful to biological control workers, taxonomists, ecologists, and anyone interested in phytophagous beetles.
Technical Abstract: Dioscorea bulbifera, a climbing vine from Asia, is a pernicious invasive plant in the southeastern USA. The plant rarely flowers but propagates by way of potato-like bulbils formed in leaf axils, which persist into the next growing season. Lilioceris cheni Gressitt & Kimoto, a foliage-feeding leaf beetle (Coleoptera: Chrysomelidae: Criocerinae) from Nepal, had been tested as a biological control agent. It proved to be an extreme specialist and was approved for release. Delays in the regulatory process, however, resulted in the demise of quarantine-held colonies and acquisition of new stock from Nepal proved untenable. Searches therefore undertaken in southern China resulted in the collection of over 300 similar beetles. Two Chinese Lilioceris species were identified in this collection: one confirmed to be L. cheni and the other identified as L. egena (Weise). Subsequent mitochondrial molecular analysis revealed an exact DNA match between some Chinese and one of the two original Nepalese COI haplotypes. While displaying diversity, all Chinese L. cheni haplotypes clearly clustered as a single species. Nonetheless, diligence was exercised to ensure that the Chinese strains were as safe to release. Abridged host testing using critical non-target test species verified host specificity but the comingling of the two species aroused concerns over possible hybridization. These concerns were allayed by further nuclear D2 analysis showing the absence of dual parental sequences. Caged field releases during autumn 2011 documented the ability of adult beetles to overwinter in south Florida despite a prolonged lack of foliage for sustenance. Open releases made the following spring and summer established vigorous populations within 6 mos that caused extensive localized defoliation with young, terminal growth almost completely consumed. Preliminary observations indicate that L. cheni now contributes to the control of D. bulbifera and the addition of the bulbil-feeding L. egena, presently under study, should complement these effects.