Submitted to: International Symposium on Biological Control of Weeds
Publication Type: Proceedings
Publication Acceptance Date: 1/22/2008
Publication Date: 12/31/2008
Citation: Antonini, G., Audisio, P., Dibiase, A., Rector, B.G., Cristofaro, M., Smith, L., Biondi, M., Bon, M., Korotyaev, B., Konstantinov, A. 2008. The importance of molecular tools in classical biological control of weeds: Two case studies with yellow starthistle candidate biological agents. International Symposium on Biological Control of Weeds.
Technical Abstract: Molecular analyses may play a primary role in the process of host-specificity evaluation at species and population levels; here are reported two examples of their application with new candidate biocontrol agents for yellow starthistle (YST). Ceratapion basicorne is a root-crown boring weevil that showed strict host specificity for YST in extensive laboratory and field tests. During the latter, genetic analyses allowed to identify immature insects from test plants, putting the final (positive) word on C. basicorne monophagy. As a result, in 2006 the insect was petitioned for release in the USA. The flea beetle Psylliodes chalcomerus was selected as a candidate biocontrol agent for YST, when an apparently YST-specific sub-population was found in the N. Caucasus in sympatric conditions with a more oligophagous sub-population associated with Scotch thistle. This finding was confirmed by laboratory and field cage trials. Since it is not possible to distinguish the two sub-populations by means of morphological characters, genetic analyses were used for this purpose. Results showed the existence of a 3% divergence between the two groups showing different host preference. An upcoming project will focus on coupling genetic analyses with host-range tests, leading to a non-destructive molecular barcoding system to "certify" individual insects.