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United States Department of Agriculture

Agricultural Research Service

Research Project: Biological Control of Invasive Terrestrial and Riparian Weeds in the Far Western U.S. Region, with Emphasis on Thistles, Brooms and Cape-ivy

Location: Exotic and Invasive Weeds Research

Title: Host specificity of an Italian population of Cosmobaris scolopacea (Coleoptera: Curculionidae), candidate for the biological control of Salsola tragus (Chenopodiaceae)

Authors
item Cristofaro, Massimo -
item Lecce, Franc -
item Paolini, Alessandra -
item Di Cristina, Francesca -
item Bon, Marie-Claude -
item Colonnelli, Enzo -
item Smith, Lincoln

Submitted to: International Symposium on Biological Control of Weeds
Publication Type: Proceedings
Publication Acceptance Date: August 14, 2012
Publication Date: May 3, 2013
Citation: Cristofaro, M., Lecce, F., Paolini, A., Di Cristina, F., Bon, M., Colonnelli, E., Smith, L. 2013. Host specificity of an Italian population of Cosmobaris scolopacea (Coleoptera: Curculionidae), candidate for the biological control of Salsola tragus (Chenopodiaceae). In: Y. Wu, T. Johnson, S. Sing, S. Raghu, G. Wheeler, P. Pratt, K. Warner, T. Center, J. Goolsby and R. Reardon (eds.), Proceedings of the XIII International Symposium on Biological Control of Weeds.USDA, U.S. Forest Service, FHTET-2012-07.pp.20-25.

Technical Abstract: Russian thistle, Salsola tragus L. (Chenopodiaceae) is a troublesome weed infesting the drier regions of western North America. It is native to Central Asia and infests rangelands and semi-arid pasture lands, croplands, residential, disturbed and industrial areas. Cosmobaris scolopacea (Germar) is a weevil distributed in Eurasia and North America, and generally associated with plant species of the family Chenopodiaceae. The larvae feed and pupate within the stems of the host plant, and the adults emerge in the following late spring. From preliminary host range testing carried out at the ENEA-BBCA facilities in Rome, Italy, it appeared that C. scolopacea might harbour different host races, one being potentially more specific to the target and only present in Sicily, Italy. To determine species boundaries and reveal population structure at the intraspecific level, a phylogeographic study using the mitochondrial COI gene was conducted on specimens collected in the native range (Italy, Spain, Iran, Bulgaria, Turkey) and the U.S.A. The study confirmed the presence within the species of a highly divergent Sicilian lineage that has only been reared from Salsola kali. The degree of specificity of this particular lineage and hence host race status is being tested through host specificity testing. Preliminary results seem to indicate that this Sicilian lineage can be at least a true Salsola host race, opening doors for further testing as a biocontrol agent for Russian thistle.

Last Modified: 10/22/2014
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