In 1989, the first cases of chestnut blight were recognised in Portugal. Quarantine measures for this A2 quarantine organism (OEPP) were not sufficient to control the disease and a program to eradicate chestnut blight was implemented in 1998.
The distribution and incidence of chestnut blight were surveyed in Braganca and Vinhais, in the Tras-os-Montes region in the north of Portugal where chestnut groves are economically important. The survey found that all communities have blighted chestnut trees except one in Braganca and one other in Vinhais. Braganca has an average of 10.3% blighted chestnut trees and Vinhais 8.0%, but the disease incidence varied greatly among different communities and among sample sites in the same community.
Based on the merging/barrage response, four vegetative compatible types were detected in eight sub-populations of C. parasitica studied in the region of Tras-os-Montes (P-1, P-2, P-3, P-5). P-2 is the most frequent and the only type present in five sub-populations of C. parasitica. More vc types were found in Vinhais where there was one sub-population with P-1, one with P-3, and one with P-1 and P-2, P-5 was found only once, and it showed a barrage response with all other testers.