【摘要】 通过对大棚黄瓜霜霉病发病率、病情指数与相对湿度的相关性分析,结果表明,(1)日均相对湿度≥80%累计天数与发病率和病情指数呈显著的线性正相关,累计天数4～5d以内时,发病率≤20%,病情指数10左右;(2)相对湿度≥80%、≥90%逐时累计量与发病率和病情指数均呈线性正相关,且灵敏度相当,当相对湿度≥80%累计时数达到140h或≥90%累计时数100～110h时,霜霉病发病率达到20%左右,病情指数为10;当相对湿度≥80%累计时数达到450～500h或≥90%累计时数达到300h时,发病率达到100%,病情指数达到50;(3)5d新增病株率随相对湿度≥80%累计天数(时数)增加呈指数增长,5d新增病情指数与后者呈抛物线关系,当≥80%累计天数(时数)为14d(450h)时新增病情指数达到最大。更多还原

【Abstract】 Through the correlation analysis of downy mildew (DM) of cucumber between the disease rate (DR), disease index (DI) and relative humidity (RH) in greenhouse, the results indicated that: (1)the DR and DI had significant positive linear correlation with cumulative days of average RH≥80%, when cumulative dates of 4~5, DR≤20%, DI≈10; (2)the cumulative hours (CH) of RH≥80% and ≥90% had positive linear correlation with the DR and DI, and they had similar sensitivity, when CHRH≥80%= 140 h or CHRH≥90% =100-110 h, DR≈20%, DI≈10; when CHRH≥80%=450-500 h or CHRH≥90%=300 h, DR=100%, DI=50; (3)the rate of new infection of 5 days grew exponentially with cumulative days (hours) of RH≥80%, the increase of DI had a parabola relationship with the latter, when cumulation days (hours) of RH≥80% was 14 d (450 h), the increase of DI reached maximum.更多还原