Monitoring of Ralstonia solanacearum in the Veneto region (Italy)

Ralstonia solanacearum first appeared in the Veneto region in 1995 following the importation of seed potatoes from The Netherlands. An epidemiological study found a total of 25 fields to be contaminated and two cultivars involved (Primura and Liseta). The seed potatoes used to plant these fields all came from one Dutch producer. The disease appeared in a very serious form, indicating that the Veneto area is favourable to its expression. A description is given of the control measures adopted. Monitoring of the contaminated fields, the potentially contaminated fields and the surrounding areas in 1995 and 1996 did not reveal the presence of the bacterium in volunteer potatoes or in potato crops. Indicator plants cultivated in a contaminated field in the spring of 1996 showed no signs of the disease. The apparent lack of efficient sources of inoculum in 1996 may be explained by the effectiveness of the control measures adopted as well as environmental factors.