Biological characteristics of a pathogen of turfgrass root rot disease

The chief pathogen was identified as Pythium aphanidermatum and its morphology,cultural characteristics and pathogenicity were investigated.The optimal temperatures for fungal growth were 30-35℃ but it could grow in the range 15-40℃.The temperature range for sporangium production was 15-25℃.The best pH was 7-8 for hyphal growth,9-10 for sporangium development,six for oospore development.The best cultural condition for mycelial and oospore growth was 24 h in the dark while the optimum treatment for sporangium growth was 24 h under light.Ultraviolet irradiation can accelerate the growth of hyphae and sporangia but it inhibits oospore production.The best source of carbon was amylum and the best source of nitrogen was ammonium nitrate.