Artificial infection of Cirsium arvense with the rust pathogen Puccinia punctiformis by imitation of natural spore transfer by the weevil Ceratapion onopordi

P>Cirsium arvense is a noxious perennial weed. Because of the limited possibilities of chemical and physical control of this weed, many studies have been performed on biological methods. Successful control of C. arvense using the rust fungus Puccinia punctiformis needs the establishment of systemic infection, often connected with the weevil Ceratapion onopordi as a spore vector. To analyse whether an artificial infection of C. arvense with P. punctiformis through the plant stem is possible without the weevil, different infection tests were performed. Urediniospore solutions with different kinds of additives of weevil origin were applied. All treatments with infectious material led to an infection. Injection of pure urediniospores into the plant stem resulted in the highest infection rate (50%). Even though the infection-via-the-stem-method used in this study was successful in principle, this method is not practicable in the field. Therefore, further studies of infection techniques are needed, particularly to examine the spore stages that cause systemic infections.