|Mann, Kimberly - Kim|
Submitted to: International Symposium on Biological Control of Weeds
Publication Type: Proceedings
Publication Acceptance Date: 1/15/2000
Publication Date: 12/1/2000
Citation: CRISTOFARO, M., LECCE, F., CAMPOBASSO,, G., TERRAGITTI, G., SPENCER, N.R., MANN, K.D. INSECT-PLANT RELATIONSHIPS AND BEHAVIORAL OBSERVATIONS OF THE STEM-FEEDING BEETLE THAMNURGUS EUPHORBIAE KUSTER (COLEOPTERA: SCOLYTIDAE), A NEW BIOCONTROL AGENT FROM ITALY TO CONTROL LEAFY SPURGE IN THE U.S. PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON BIOLOGICAL CONTROL OF WEEDS. 2000. p. 615-619.
Technical Abstract: Thamnurgus euphorbiae Kuster (Coleoptera: Scolytidae) adults are found in early spring on flowering plants of Euphorbia characias in Italy. The hypothesis was that T. euphorbiae beetles recognize the host plant at the correct phenological stage by its specific odor. Behavioral bioassays were conducted under choice and no-choice conditions to verify the capability of fthe insect to detect the target weed leafy spurge (E. esula). A wind tunnel and two-way-olfactometer were used in no-choice bioassays to expose the insect to the odor of the host plant at different phenological stages. The results did not show any response of the beetle to the host plant volatile compounds. In choice tests, the beetle showed a preference for bud stage stems vs. flowering stems with the top covered by dark cotton net. This result can be explained only by a visual attraction of the insect to the shape of the stems, since green leaves covered the 20cm bud stage stems, while the flowering stems were almost leafless.