Prospective Insect Biological Control Agents of Yellow Starthistle and Scotch Thistle in Turkey
Exotic and Invasive Weeds Research
2012 Annual Report
1a.Objectives (from AD-416):
Yellow starthistle and Scotch thistles are important invasive weeds in the western USA that originated from the Mediterranean Region. Little is known about insects attacking these plants in Turkey. We will determine the identity, host specificity and impact of insects attacking these plants in Turkey to assess their potential as biological control agents.
1b.Approach (from AD-416):
Surveys will be conducted in Turkey to find insects that attack yellow starthistle and Scotch thistle. The taxonomic identity of insect species will be determined, and information on geographic distribution and known host plants will be summarized. Experiments will be conducted to evaluate the host plant specificity and potential impact on the target weed of the most interesting insect species under field and/or laboratory conditions. Live specimens will be sent to the USDA-ARS quarantine laboratory for further host specificity studies with native North American plant species.
This research addressed Objective 2 of the parent research project, documenting the host-specificity and safety of new biological control agents. Over the course of this project, exploration was conducted in the Mediterranean region for prospective biological control agents of yellow starthistle and Scotch thistle. A field experiment was conducted in Igdir, Turkey, where we released Larinus filiformis, a prospective agent of yellow starthistle, and Larinus latus, a prospective agent of Scotch thistle to evaluate their potential risk to nontarget plant species. Results are incomplete because we are still rearing out adult insects, but so far Larinus filiformis has attacked only yellow star thistle, and Larinus latus has attacked only Scotch thistle. Specimens of Larinus filiformis were sent to our quarantine laboratory where we are conducting experiments to evaluate host plant specificity.