长江下游棉花落叶型黄萎病发生消长与气象因子关系分析

Analysis on the Relationship Between the Defoliating Type of verticillium Wilt and Meteorological Factors in Lower Reaches of Yangtze River Valley

１９９３～１９９７ 年， 在江苏省常熟市徐市镇棉花落叶型黄萎病地（致病小种为落叶型ＪＣ５），对苏棉８ 号从６ 月初至９ 月中旬进行棉花黄萎病调查， 并结合当地的气温、雨日等气象因子对黄萎病的发生消长关系进行统计分析。结果表明， 平均气温２３℃最适宜发病， 平均气温大于２８℃时发病停止（隐症）。黄萎病的日增病指与平均气温、雨日相关性较强， 与雨量相关性较差。合并５ 年的资料， 通过多因子筛选， 得出日增病指（Ｙ）与雨日（Ｘ２）、大于２３℃的有效积温值（Ｘ１）的关系式： Ｙ＝ － ０．１４９４９Ｘ１＋ ０．１４５４４Ｘ２＋ ０．９３５５１。

The experiment was conducted at the seriously infected cotton fields with defoliating type of verticillium wilt JC 5 in Changhu city, Jiangsu, lower reach of the Yangtze river, from 1993 to 1997. The disease incidence of susceptible cotton cultivar, Sumian8 in the same field was investigated for 5 years successively. In the meantime, the correspondent weather factors from early June to middle September were acquired to analyze the relationship between the disease incidence and weather factors. The result showed that disease development was significantly related to temperature,raining day except precipitation. As of the temperature, high temperature could inhibit the development of the verticillium disease. 23℃ was an turning point because temperature over 23℃ was unfavorable to the disease development. The disease development totally ceased if the average temperature was over 28℃. The equitation, Y=-0.14949X 1+0.14544X 2+0.93551 was inferred to describe the relationship among daily disease development (Y), raining day (X 2) and thermal constant (X 1>23℃) based on the 5 year data.