BIOLOGICAL CONTROL OF INVASIVE TERRESTRIAL AND RIPARIAN WEEDS IN THE FAR WESTERN U.S. REGION, WITH EMPHASIS ON THISTLES, BROOMS AND CAPE-IVY
Location: Exotic and Invasive Weeds Research
Title: Status of biological control projects on yellow starthistle, Russian thistle, Scotch thistle, Cape-ivy and French broom
Submitted to: Western Society of Weed Science
Publication Type: Abstract Only
Publication Acceptance Date: December 13, 2011
Publication Date: March 12, 2012
Citation: Smith, L. 2012. Status of biological control projects on yellow starthistle, Russian thistle, Scotch thistle, Cape-ivy and French broom. Western Society of Weed Science. [abstract].
The USDA-ARS quarantine laboratory in Albany, CA, in cooperation with foreign scientists, is currently developing classical biological control agents for five species of invasive alien terrestrial weeds. Host specificity testing of the yellow starthistle rosette weevil, Ceratapion basicorne, indicates that it does not attack safflower under field conditions and that it has low preference for bachelor's button. Host specificity tests are being conducted on a weevil, Larinus filiformis, that attacks seedheads. The eriophyid mite, Aceria salsolae, which stunts Russian-thistle, can attack six closely related species of Salsola and sometimes multiply on Bassia hyssopifolia and Bassia scoparia in no-choice laboratory experiments. A stem-boring seed-feeding caterpillar, Gymnancyla canella, is being evaluated for specificity. For Scotch thistle control, three weevils (Larinus latus, Trichosirocalus briesei and Lixus cardui) that have been released in Australia are being evaluated for risk to native thistles (Cirsium spp.). A petition has been submitted to USDA-APHIS requesting permission to release two agents of Cape ivy: a gall-forming fly, Parafreutreta regalis, and a stem-boring moth, Digitivalva delaireae. For French broom, a psyllid, Arytinnis hakani, that is killing plants in Australia is being evaluated for risk to native lupines.