4d.Progress report.
This report serves to document research conducted under a specific cooperative agreement between ARS and the Biotechnology and Biological Control Agency, Rome, Italy. Additional details of research conducted under this project can be found in the report for the parent CRIS 4012-22000-023-00D, "Discovery and Initial Development of Classical Biological Control Agents for Invasive Eurasian Weeds Affecting Agricultural and Natural Areas." During 2006 BBCA continued the work on the following target weeds: yellow starthistle (YST), Russian thistle, and saltcedar in co-operation with USDA-ARS Albany, CA and USDA-ARS Reno, NV; and on perennial pepperweed (PPW) in co-operation with the above cited and with CABI, Delemont, Switzerland. Yellow starthistle: Aim of this study was to define the population genetics of the insect in relation to its host specificity in order to identify other YST-specific populations, adapted to different climatic conditions. Results showed a clear-cut homogeneity of the different genotypes, suggesting the existance of a continuous gene-flow among the populations and/or of a strict association to the host within all populations examined. Moreover, host-range choice and no-choice tests carried out on the Italian population showed similar results to the ones obtained with the E. Turkish insects. Altogether, such outcomes confirm and strengthen the evidence that C. basicorne is suitable as a safe biocontrol agent for YST in different climatic conditions (in co-operation with USDA-ARS EBCL). Completed the host specificity assessment of the lace bug Tingis grisea which were started in 2003, adding choice and no-choice oviposition trials on 16 plant species. Preliminary analyses of the results suggest that the insect has probably a too wide host range, although limited to the genus Centaurea, to be suitable for introduction in the USA for YST biocontrol. During the next few months, BBCA will complete the data analysis and will write one publication reporting the whole study. Carried out field collections and consequent laboratory rearing of the tephritid flies Chaetorellia spp. in order to provide pre-imaginal stages to USDA-ARS, Albany. Carried out laboratory and field tests on a new diet developed by USDA-ARS, Albany, CA, for the development of pre-imaginal stages of root and stem boring insects. Russian thistle: Collected the candidate biocontrol agent Anthypurinus biimpressus in Tunisia. Carried out no-choice introductory trials on several Salsola spp. and other commercial Chenopodiaceae. Results showed that the insects were able to oviposit and larvae to grow only on S. kali, S. tragus and S. soda. Reared out F1 but we couldn't set-up a permanent lab colony. During the trials we also used the insect diet mentioned above with positive results. Carried out extensive field surveys in Kazakhstan, selecting several flea beetles and root/stem boring weevil species. The insects are currently being identified. Perennial pepperweed: Carried out field surveys in Turkey and Kazakhstan in order to define the guild of insects associated with PPW and to select among them new potential biocontrol candidates. Following last year's preliminary field surveys, several weevils, one Chloropid fly and other unidentified flea beetles were selected. Several plant pathogens were also found. Started to carry out biological observations on the Chloropid flies in laboratory. Saltcedar: Carried out field surveys in Turkey, Kazakhstan and Italy in co-operation with USDA-ARS, Albany, CA and USDA-ARS, Reno, NV, targeted to the selection of natural enemies of T. parviflora and T. canariensis.