1 Zoospore An asexual motile spore produced by a zoosporangium.

2 There was no correlation between zoospore and sporangium yeild in different medium.

3 The production condition of zoospore of P. sojae was studied. The results showed that the mycelia could be induced to produce sporangia that released zoospores by changing intermittently.

4 The biological characteristics of growth rate and colony morphology of single–zoospore isolates were studied.

5 Its homothallic character was maintained in single sporangium or single zoospore isolates. Pathogenic experiments proved that this strain is a typical P. infestans.