The efficiency of Dienes` stain and three fluorochromes, i.e., 4`, 6-diamidino-2-phenylindole (DAPI), aniline blue(AB) and quinacrine for the detection of paulownia witches`-groom mycoplasma (PWM) infection in paulownia trees were investigated under the light and fluorescence microscope. When PWM affected leaf and stem sections were stained with DAPI, AB and quinacrine respectively, distinctive mycoplasma specific fluorescence appeared in the phloem tissue of the section, while no floorescence was observed from phloem tissue of healthy paulownia, Dienes` stain, a useful stain for detection mycoplasma infection under the light microspope, however, did not distinguish PWM affected paulownia from healthy paulownia. Among the three fluorochromes compared, DAPI appeared to be most efficient for detecting PWM infections in the phloem tissue of paulownia. Both 5% glutaraldehyde and 4% formalin were found to be effective as fixing agents for floorochrome staining. For the aniline blue staining, fixing of the tissue sections in boiling-water gave satisfactory results.