|Smith, Lincoln - Link|
Submitted to: XI Symposium on Biological Control of Weeds
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2003
Publication Date: 6/1/2004
Citation: Cristofaro, M., Dolgovskaya, M.Y., Konstantinov, A., Lecce, F., Ya.Reznik, S., Smith, L., Tronci, C., Volkovitsh, M.G. 2004. Psylliodes chalcomera (illiger) (coleoptera: chrysomelidae: alticinae), a flea beetle candidate for biological control of yellow starthistle centaurea solstitialis. In: Cullen, J.M., Briese, D.T., Kriticos, D.J., Lonsdale, W.M., Morin, L., and Scott, J.K., editors. Proceedings of the XI Symposium on Biological Control of Weeds, April 27-May 2, 2003, Canberra, Australia. p.75-80. Interpretive Summary: Yellow starthistle is an important rangeland weed in the western U.S.A. Previously released agents appear to be having little impact, except in Oregon, at low elevation sites that have healthy grass communities. Thus, additional species are being evaluated as potential biological control agents. The flea beetle, Psylliodes chalcomera, which has stem-boring larvae and leaf-feeding adults, seems to be one of the most promising species. This species has been collected on different host plants (yellow starthistle, Scotch thistle, and musk thistle) in Europe. It was suspected that there might be several host-specific cryptic species or biotypes. Field and laboratory experiments showed that there are at least three biotypes of this "species" that are adapted to the three different host plants.
Technical Abstract: Separate populations of the flea beetle, Psylliodes chalcomera, were collected in Russia on yellow starthistle and on Scotch thistle. No-choice laboratory studies showed that the insects survived longer and laid many more eggs on their preferred host plant than on the other two. In no-choice and choice experiments the two populations severely damaged or killed the host plant species from which they were originally collected and caused medium or little damage to the other plants. Two insect populations collected in Italy on musk thistle, and in choice experiments none of the insects laid eggs on safflower and very few laid eggs on yellow starthistle or Scotch thistle. Field studies on naturally occurring yellow starthistle plants revealed a negative correlation between plant biomass and insect infestation, suggesting that this insect significantly damages plant. No morphological differences were found that could reliably distinguish between the three biotypes. Further genetic and host specificity studies will be conducted.