棉花不同播期对黄萎病发生规律的影响

Preliminary Study on Effect of Different Seeding Dates on Regularity of Development of Cotton Verticillium wilt

对２个品种在７个不同播期的平作棉与麦套棉进行棉花黄萎病发生规律的研究。结果表明，不同播期的黄萎病发生规律存在着差异，尤其对黄萎病侵染和扩展具有较大的影响。４月３０日，５月７日，５月１４日，５月２１日播种的４个处理，２个品种的黄萎病侵染扩展速度较慢，９月１０日播种的平作棉的黄萎病株率均低于３７５％，麦套棉的病株率均在３７０％以下，６次调查病情指数总和与４月９日，１６日，２３日播种的３个处理相比，达显著水平。不同播期平作棉的黄萎病全年为２个发病高峰，５月份播种的第１个发病高峰推迟，４月３０日播种的发病高峰值较低；４月９日，１６日，２３日播种的麦套棉全年发生３个发病高峰，其它播期为２个发病高峰。

The results showed that the regularity of cotton Verticillium wilt were different in 7 seeding dates in cotton single cropping and wheat cotton double cropping field. Sowing seed on April 30, May 7, 14, 21, the infecting and developing of cotton Verticillium wilt were slowly, and damage rate was lower than 37.5% on September 10 in cotton single cropping field and lower than 37.0% in wheat cotton double cropping field. The total of disease index was significant difference compared with seeds sown on April 9, 16 and 23 in cotton single cropping field. In cotton single cropping field, there were two occurrence peaks. The first occurrence peak was delayed in May of sowing seed, and the occurrence peak value was lower for seeds sown on April 30.In wheat cotton double cropping field, there were three occurrence peaks for seeds sown on April 9, 16 and 23 all throug the year. There were two occurrence peaks in other sowing dates.