Evidence of the Presence of the Tobacco-Etch Virus in Puerto Rico

Abstract

A new virus disease was found in cigar-filler and chewing-tobacco plants in Puerto Rico, in 1954. The infected plants developed chlorotic spots on the younger leaves followed by the presence of necrotic spots, arcs, and sometimes rings as the leaves became older. The younger leaves also appeared slightly chlorotic. Chewing tobacco is more severely affected than cigar-filler tobacco. The virus is easily transmitted mechanically by plant sap. It was also found to be transmitted by the aphid Myzus persicae. The virus was identified by using the method proposed by Valleau (6) to identify viruses that are found causing disease in commercial plantings of tobacco, and by serology, using the method recommended by Bawden (1). Antisera for tobacco severe-etch virus was used. It was found that the virus that causes what is referred to as el salpicado del tabaco in Puerto Rico is related to the etch virus. The variety of symptoms observed suggest that besides severe etch the mild- and coarse-etch strains of the virus may also be present in Puerto Rico.