Studies on the survival of Ralstonia solanacearum on different types of packing material
Boxes and bags used for transport and storage of potatoes may be contaminated by Ralstonia solanacearum (EPPO A2 list) and ensure further spread of the disease over short or long distances. Studies were done in Italy on the survival of R. solanacearum on poplar and oak wood, high-density polyethylene, and jute bags in cold storage (4°C). Samples of wood, polyethylene and jute were immersed in a bacterial suspension. After air-drying at room temperature, material was stored in open trays in a cold store (4°C and 80-90% HR). Survival was assessed on concentrates obtained by washing samples of contaminated materials, centrifugation of washing liquids and plating onto selective media. Results showed that R. solanacearum survived on oak wood for approximately 4 days and on poplar wood for 17 days. On high-density polyethylene, after 2 days no bacterium survived. On jute fabric, the number of living bacteria dropped considerably after 24 hours, but survival was zero only after 78-108 days. It is concluded that jute sacks contaminated with rotting or exuding infected tubers are a probable source of inoculum and a means for further dissemination of the disease. As a consequence, jute bags should be thoroughly cleaned before being reused.
Sources
Pasqua di Bisceglie D, Saccardi A, Giosue S, Traversa F, Mazzucchi U (2005) Survival of Ralstonia solanacearum on wood, high density polyethylene and on jute fabric in cold storage. Journal of Plant Pathology 87(2), 145-147.