Un nuevo virus aparecido en tabaco.

Spanish; Castilian. Un nuevo virus se ha hallado afectando las plantaciones de tabaco en Cuba, con mayor intensidad en la provincia habanera. Este se caracteriza por presentar síntomas de necrosis sistémica ascendente en Nicotiana tabacum L. de las variedades Criollo y Samsun. Su mayor actividad la presenta a las temperaturas mas bajas del invierno en nuestro país deteniéndose en parte su avance en temperaturas de verano (mayores de 25°C). Sólo se ha podido transmitir este virus por semilla, pues las pruebas de transmisión por medios mecánicos resultaron negativas. No se halló relación serológica entre este y el virus de la necrosis del fruto del tomate (tomato internal browning). El autor estima que podría tratarse de la enfermedad aparecida en Kentucky y otras zonas tabacaleras de E. U. A. llamada 'fleck'.

English. A new virus has been discovered which affects tobacco plants grown in Cuba. It's highest concentration is in Havana province. The presenting sympton is an ascending systemic necrosis, found in Nicotiana tabacum, Criollo and Samsun varieties. Symptoms are most intense at lower temperatures (in our country, during the winter) and remit in part during the summer (at temperatures higher than 25°C.). It has only been possible to transmit this virus by seed. All attempts at direct transmission by mechanical methods have given negative results. Apparently this is a seed born virus. No serological relation was found between it and the virus which causes necrosis of the tomato (tomato internal browning). The author believes that this virus may the same etiological agent which has caused tobacco blights in Kentucky and other parts of the U. S., and which is known as fleck.