In December 2014, some growers received word that the plant material they purchased may have been infected with Ralstonia solanacearum (southern bacterial wilt). Host material was grown in Guatemala, shipped weeks 30-52, and included callibrachoa, heliotrope, lobelia, nemesia, osteospermum, petunia, portulaca and verbena (please note that the host range is broader than this list).
It is important to note that the Ralstonia found is Race 1, not Race 3 Biovar 2 which is a quarantine pathogen. However, growers were requested to destroy the plant material, test suspected plants, and disinfect floors and benches with which the plants may have been in contact. NYS Ag and Markets inspectors have visited all greenhouses that were known to have received the suspect plant materials.
Race 1 has a wide host range and is regularly found in the southern US. It is not considered to spread easily – for example, it is not spread by splashing although it could be spread through the use of ebb and flood benches. However, it is important to remove all infected plants from the greenhouse as soon as possible.
If you notice wilting in geranium, tomato or eggplant, pay particular attention, as they are also hosts of the more serious Race 3 of Ralstonia.
If you have plants of a host species with wilted leaves – often on one side of the plant or only one side of a leaf – and suspect Ralstonia, you can test the plants using test kits from Agdia (http://www.agdia.com/). The test kits will not tell you which race is present, so plants that test positive should be sent to a diagnostic lab for additional testing.
For more information on Ralstonia solanacearum, go to: http://extension.psu.edu/pests/plant-diseases/all-fact-sheets/ralstonia.