Pathogen identification of Bidens pilosa powdery mildew

In order to make clear the phylogenetic evolution relationship of Bidens pilosa powdery mildew detectedin Guangzhou，China，morphological，etiological and molecular systematic identification were tested. Results show thatconidiophores were measured with 100 - 160 μm × 11 - 13 μm，and they produced 2 to 4 immature conidia in chainswith a crenate outline and 1 to 2 straight cells of the conidiophore at the terminal. Conidia were oval-shaped to roundshaped，hyaline，and measured with 20 - 50 μm × 10 - 20 μm（length/width ratio of 1.25 - 3.0）. The fungus appearingon the inoculated plants had the same morphology with those from original diseased plants. Internal transcribed spacer（ITS）sequences of its ribosomal DNA were amplifild by PCR， 528 bp sequences（GenBank：KJ920100） were obtained，and sequence analysis by MEGA3.1 software revealed that sequence of pathogenic bacteria and KF453969 fromGolovinomyces cichoracearum gather together with 99% of similarity. The results show that pathogen of B. pilosa powderymildew in Guangzhou is G. cichoracearum.