Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

First report of bacterial wilt of tomato (Solanum lycopersicum) caused by Ralstonia solanacearum in Benin.

Abstract

In June 2004, wilted tomatoes with no foliar yellowing were observed in Ouègbo, Atlantique District, Benin. The cut tomato stems released whitish bacterial ooze. Longitudinal sections of most stems showed brown vascular discoloration. Bacteria were isolated on triphenyl tetrazolium chloride (TTC) medium and three of the nine bacterial isolates that resembled Ralstonia solanacearum (colonies with red centre and whitish pheriphery) and reference strain ToUdk (race 1 biotivar 3) were used for pathogenicity tests. R. solanacearum was recovered from 20 symptomatic plants on TTC medium. Because similar symptoms were being increasingly reported by farmers across Benin and linked with reduced tomato yields, a disease survey was undertaken by IITA in 2006 and 2007. Wilted tomato plants were found across all agro-ecological zones of Benin (3-72% of plants per field). Isolates were recovered from the southeastern districts of Adja-Ouèrè, Sakété, Adjohoun and Dangbo, the southwestern districts of Klouékanmè and Athiémé, the southern districts of Toffo and Bohicon, the central districts of Dassa ang Savé, and the northern districts of Malanville and Karimama. This is thought to be the first report of R. solanacearum infecting tomato in Benin.