POPULATIONS OF PHYTOPHTHORA-INFESTANS (MO NT)D BY IN RUSSIA AND IN SOME COUNTRIES OF THE FORMER USSR

The populations of Phytophthora infestans collected during 1985-1994 i n Belorussia (35 strains), Estonia (2 strains), Moscow region (120 str ains), the Caucasus (strains), the Urals (7 strains) and the Tomsk reg ion (Siberia, 7 strains) were studied as to their mating type, vegetat ive compatibility groups and response to metalaxyl. The Moscow region populations in 1991 were quite similar, in all of them the metalaxyl-r esistant strains were predominated and the frequency of the strains wi th A2 mating type was near 50 %. But in 1993 in Moscow region one popu lation which was earlier resistant to metalaxyl became predominantly s ensitive, the other population was represented by only metalaxyl-resis tant strains. In both these populations the A1 mating type was predomi nated. A1l other populations from the former USSR comprised the strain s with only A1 mating type and the metalaxyl-sensitive strains were pr edominating. The populations of P. infestans near Moscow were more sim ilar to Polish and Dutch populations than to Belorussian and Siberian populations of P. infestans. It may be connected with potato export in Russia from Poland in the 1980s and from Netherlands in the 1990s.