Abstract: Based on field experiment data and with statistical method, this paper analyzed the relationship of range, time and frequency of high-temperature controlling with periods of development and prevailing of cucumber downy mildew, its damage degree and cucumber yield. Relative models were established and technic indices of high-temperature controlling method were defined. Three main indices (maximum temperature, period of hightemperature controlling and controlling frequency) relate closely to damage degree and cucumber yield. If the maximum temperature raises by 1℃, periods of disease development and prevailing will delay by 3—5 days, percentage of damaged leaf will decrease by 13—15% and cucumber yield will increase by 10% or so. Within a definite range, longer controlling period and higher controlling frequency will induce a later disease development and prevailing period, lower damage degree and higher cucumber yield. It is proved that high-temperature controlling method is an effective ecological prevention way, which has a definite climate-ecological basis.

Key words: Cucumber downy mildew, High-temperature controlling, Correlation analysis, Ecological prevention index