Abstract Text: Canada thistle (CT) is a perennial noxious weed which reduces crop yields and forage quality in the northern United States, Canada, Australia, New Zealand, Asia and Europe. CT is resilient to many environmental stresses and subsequently it is difficult to control or eliminate. In addition, herbicide treatments are not an economical option for forest landscapes. Puccinia punctiformis is a rust pathogen specific to CT. Two types of infection can occur with P. punctiformis. The first type is a systemic infection caused by urediospores or basidiospores, mycelia establishes in the rhizomes resulting in pale green shoots which are stunted and rarely flower. The second type of infection is local, resulting from urediospore infection which may become latent after leaf senescence. Since P. punctiformis is an obligate plant pathogen with CT being the only host, it is a good choice as a biocontrol agent. In order for this system to be effective, there needs to be reliable and high rate of infection of CT by P. punctiformis. Research demonstrated that extracts of CT root can increase the rate of P. punctiformis teliospore germination and enhance infection. We have developed a hydroponics system to grow CT to provide a reliable source of CT root tissue for teliospore germination cue to enhance the rate of P. punctiformis CT infection. In addition, we are working to optimize PCR primers for the detection of P. punctiformis. This detection tool will then be used to monitor P. punctiformis infection of CT. These tools will be used to improve CT management in forest and range settings.
