POPULATION STUDIES ON PHYTOPHTHORA INFESTANS IN FINLAND AND NORWAY
A HERMANSEN1, M B BRURBERG1, A HANNUKKALA2 and R HAFSKJOLD3
1The Norwegian Crop Research Institute, Plant Protection Centre, Dept. of Plant Pathology, Fellesbygget, N-1432 Ås, Norway; 2Agricultural Research Centre, Institute of Plant Protection, FIN-31600 Jokioinen, Finland, 3Agricultural University of Norway, Dept. of Horticulture and Crop Sciences, PO Box 5022, N-1432 Ås, Norway
Background and objectives
Materials and methods
Results and conclusionsBoth mating types were present in most regions of Finland and Norway. Metalaxyl sensitivity was occuring at different levels in the two countries. In Finland the proportion of resistant strains have decreased to a low level from the early 1990s when the blight population was fully metalaxyl resistant. In Norway more than half the number of isolates were resistant to metalaxyl in 1996. All known virulence genes were present in both countries (R9 not tested). The DNA fingerprinting analyses are at present not completed, but will be important for the conclusions drawn regarding the sexual reproduction.