Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/16/2006
Publication Date: 7/1/2007
Citation: Lartey, R.T., Caesar, T., Ghoshroy, S., Lenssen, A.W., Evans, R.G. 2007. Leaf spot of cercospora beticola: a new disease of safflower. American Phytopathological Society Abstracts. 97(7):169. Interpretive Summary:
Technical Abstract: Cercospora Leaf Spot of safflower by Cercospora carthami has only been reported in the old world. Unusual spot symptoms on safflower cv. Centennial, which is rotated with sugar beet at Sidney, MT in the Northern Plains, prompted our studies of safflower as a possible host of C. beticola, a pathogen of sugar beet. Using isolates C1, C2, Sid1 and Sid2 of C. beticola, we provided evidence that it causes leaf spot disease in safflower. Safflower plants produced spot symptoms after cross infection of sugar beet with the four isolates. The presence of C. beticola in spot lesions was confirmed by PCR. In addition, sequences of PCR amplicons confirmed the presence of C. beticola in safflower and sugar beet lesions when compared with C. beticola sequence from GenBank. Antibody from C2 also bound to samples from the lesion tissues. Finally, infection progression of isolates C2 and Sid1 in safflower with scanning electron microscope showed entry of the pathogen through stomatal openings. Lesions showed substantial hyphal mass and protruding hyphae from stomatal apertures in lesion areas, indicating presence of internalized hyphae after establishment of infection.