Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

First report of Tomato torrado virus on tomato (Solanum lycopersicum) in South Africa.

Abstract

During the 2015 growing season, tunnel- and field-cultivated tomato (Solanum lycopersicum) crops in the Limpopo Province of the Republic of South Africa developed dark brown spots on the leaves that progressed to a burnt-like appearance. Symptoms began as necrotic spots at the base of young leaves following vertical necrotic lesions on the stem. Mild chlorosis often surrounded the onset of leaf necrosis. Fruit became deformed, hardened, and blotched with necrotic tissue, making it unmarketable. These symptoms coincided with abnormally high whitefly (Bemisia tabaci) populations in the province and are similar to those previously described from parts of Europe, South America, and Australia as a result of whitefly-transmitted torrado viruses. In Mexico, similar symptoms were reported on tomato crops infected with Tomato apex necrosis virus, a member of the Secoviridae family. Based on the results of reverse transcription polymerase chain reaction, northern blot hybridization, RNA in situ hybridization and analysis of the nucleotide sequences, the causal agent was identified as Tomato torrado virus (ToTV). This is thought to be the first report of ToTV in South Africa and the mainland African continent.