Abstract
Little-leaf, a new disease of Brugmansia candida was found in Brisbane, Queensland, Australia. Petiole and stem tissues of both affected and healthy plants as well as tomato plants, graft-inoculated and uninoculated, were subjected to histochemical examination and electron microscopy for possible association with mycoplasma-like organisms (MLO). Pleomorphic bodies of MLO were detected in the phloem elements of the diseased specimens but not in healthy plants. In fluorescence microscopy with a DNA specific stain, DAPI (4', 6-diamidino-2-phenylindole⋅2HCl), these MLO fluoresced specifically. Disease specific accumulation of callose in affected phloem cells was detected after staining hand sections with aniline blue.
