Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: January 2, 2004
Publication Date: January 12, 2004
Citation: Smith, L. 2004. Prospective new agents for biological control of yellow starthistle [abstract]. 2004 Proceedings of the California Weed Science Society. 56:136. Technical Abstract: Six species of insect biological control agents have been introduced to control yellow starthistle; however, they do not appear to be sufficient to control the plant in most parts of California. A rust pathogen (Puccinia jaceae var. solstitialis) was approved in 2003 for experimental release in California, and the first release was made last July by CDFA and ARS scientists. A weevil (Ceratapion basicorne) that develops inside the root crown of rosettes is being evaluated in quarantine laboratory. So far, it appears to be safe with respect to commercial crops such as artichoke and safflower and to native species of thistles and knapweeds. Adult weevils feed on rosette leaves in late winter, and larvae develop inside the root crown and complete development by the time the plant bolts. This weevil is abundant in Turkey, attacking up to 100% of plants at a site, and many larvae can be found developing within one plant. A flea beetle (Psylliodes sp. nr. chalcomera) from southern Russia that develops in young stems has passed preliminary host specificity tests and will be studied further to see if it will be safe enough to release. Several other prospective agents are in early stages of evaluation, including: a blister mite, a lace bug, a rosette fly, a seedhead weevil, and three fungal pathogens.