Título en español.

Rod-shaped virus particles were observed under the electron microscope in negatively stained juice obtained from sugarcane mosaic-affected plants of CP31-294. The particles were of strains A and B and measured 720-1,446 nm x 14-15 nm and 720-1,730 nm x 14-15 nm, respectively. A total of 51 promising varieties of sugarcane were artificially inoculated with a mixture of mosaic virus strains A, B and D in three separate greenhouse experiments during the last 3 years. PR 1141, PR 1152, PR 62-285, PR 64-1548, PR 65- 153, PR 65-2538, Q 68 and selection Sóller were found potentially capable of taking mosaic, with an average of 10-19% infection. However, none of these varieties showed mosaic symptoms in the fields under natural infection. Therefore, they are acceptable for field planting in Puerto Rico.