In Brazil, the ornamental and flowering plant market has gained wide acceptance in the last years. It is worth
mentioning that simultaneously to the increase in the Brazilian exports, an increase in the flowers and ornamentals
imports has also been noted. However, despite the introduction of new botanical species and varieties, reports of
viral diseases are scanty, probably due the latent form of some viruses that precludes their symptoms manifestation.
The aim of this study was to identify by biological, serological and molecular means a virus in asymptomatic Torenia sp. from growing areas of the São Paulo state. In addition, an alternative control method was proposed. On mechanically
inoculated hosts, the Torenia virus induced Potexvirus-like symptoms. RT-PCR analysis was positive for Potexvirus when specific primers were used. Serological tests, sequencing and the phylogenetic analyses were conclusive for the
identification of Alternanthera mosaic virus (AltMV), herein referred to as AltMV-T. Potexviruses, and also AltMVT,
are generally spread in crops through cutting tools and contact. With the aim of efficiently and economically
controlling the viral contamination, foliar extract of Mirabilis jalapa was sprayed on Chenopodium amaranticolor prior leaf cuttings were made with blades previously dipped in the viral inoculum. It was noted that the infection by
AltMV-T was reduced at 83% in sprayed C. amaranticolor. This result indicates the potential importance of M.
jalapa extracts for reducing the virus dissemination during cultural practices in the crop.