Abstract
An acquired resistant isolate UOP393 (=IFO 32590) of Pythium vanterpoolii to metalaxyl was compared in soil for oospore germination with its parent sensitive field isolate UOP 392 (=IFO32589) . The results obtained are as follows.
(1) No significant differences were found in oospore germination in aerated steam treated field soil without plant residues between resistant isolate and its parent sensitive field isolate. But plant residues buried only promoted oospore germination of parent sensitive field isolate.
(2) In non-treated field soil, oospore germination of sensitive isolate enhanced with or without plant residues.
(3) No significant differences were found in oospore germination between resistant isolate and its parent sensitive field isolate in aerated steam treated field soil and in non-treated field soil.
