Taking ‘Luhuanggua No.3’ cucumber as test materials,the effect of temperature and moisture on survival of sporangia was studied in controlled conditions.The results showed that temperature and humidity had significant difference on survival of sporangia.The survival ratio deceased with the increase of temperature.Only 2% sporangia were survived after 24 hours treatment at 35℃.Saturated humidity was favor of the survival of sporangia and the effect of dry condition on the survival of sporangia was complicated.At dry condition (RH=45%)，the survival ratio increased with the increase of temperature，and reached the peak at 25℃，then decreased with increase of temperature.Kept in environment with constant temperature，life-span of fresh sporangia was 1 d at 35℃，3 d at 30℃ and 3~6 d at 10，15，20 and 25℃，respectively.
References:
[1]Cohen Y，Roten J.Field and growth chamber approach to epidemiology of Pseudoperonospora cubensis?cucumbers[J].Phytopath,1971,61:736-737.