Susceptibility ofCarduus, Cirsium,andCynaraSpecies Artificially Inoculated withPuccinia carduorumfrom Musk Thistle

摘要: Abstract Puccinia carduorum from Turkey was evaluated for biological control of Carduus thoermeri under controlled greenhouse and field conditions. We measured the susceptibility 16 accessions C. (the target weed), 10 related weedy spp., 22 native 2 Cirsium species, Cynara scolymus (artichoke). All collections (including 99.2% individuals) were very susceptible, as putative hybrids between other large-flowered spp. Disease incidence on nutans or macrocephalus 0 to 5% plants inoculated. Of 454 individual thistles inoculated, 83% did not develop symptoms (= immune) at any stage growth, including all individuals in 11 species. For species which observed, 75% immune when inoculated 4–5 weeks after planting, no susceptible reactions developed reinoculation these later. A similar effect plant age noted Cy. scolymus. Results those occurred also inoculations eight selected two three Switzerland. susceptible; ratings disease severity “2” “4” maximum rating). remainder highest rating “1” Despite than thoermeri, P. considered low risk because infections weak pathogen could be maintained nontarget optimal Data experiments part a proposal USDA, Animal Plant Health Inspection Service (APHIS), use United States control. Permission granted by APHIS Virginia Department Agriculture 1987 conduct study near Blacksburg, Virginia.