Studies on the host range of Ralstonia solanacearum race 3 biovar 2
Studies on the host range of Ralstonia solanacearum race 3 biovar 2 (EPPO A2 quarantine pest) were carried out in the UK and in Nepal. Common agricultural weeds and crops which grow in the high hills of Nepal were examined after artificial inoculation and under natural conditions to determine whether they could act as host plants. Results of artificial inoculation studies indicated that the bacterium could infect and multiply in the weeds Drymaria cordata, Polygonum capitata (both summer weeds), Cerastium glomeratum, Stellaria media (both winter weeds) and in the crop Brassica juncea (mustard). When sampled 3 months after harvest of a wilted potato crop, bacterial populations could be recovered from root extracts of naturally growing D. cordata plants (in 75 % of the plants), as well as in P. capitata (in 25 % of the plants). When artificially inoculated, B. juncea developed wilt symptoms. However, in natural conditions, when planted into heavily infested plots, no infection could be found. The authors concluded that the role of non-solanaceous summer weeds in the persistence of the bacterium in the environment may have been previously underestimated and that further studies are needed.
Pradhanang, P.M.; Elphinstone, J.G.; Fox, R.T.V. (2000) Identification of crop and weed hosts of Ralstonia solanacearum biovar 2 in the hills of Nepal.
Plant Pathology, 19(4), 403-413.