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为寻求最佳防治适期,选择未施农药有代表性棉田3块,采用“Z”字形取样,每3天调查一次真计数、蚜量、卷叶情况,另设出苗、2、3、4片真叶,百株蚜量为400、500、600、800、1 000、1200头共计24个处理,两次重复做接蚜试验。接蚜前用触杀剂农药控制试验区无蚜害。接蚜后每小区选20株棉花,进行调查。试验结果:在出苗至第1片真叶期,百株蚜量从0上升到300头,最后达2000头,卷叶株率上升到3.1%,最后达100%。此时棉苗耐害性差,百株蚜量在300～500头,平均卷叶株率
In order to find the best control period, we selected 3 representative cotton fields without pesticides, sampled with “Z” shape, investigated the true counts every 3 days, the amount of aphids and leaf curl, A piece of true leaves, a hundred aphids 400,500,600,800,1 000,1200 a total of 24 treatment, repeated twice to do aphids test. Aphis before taking aphids pesticide control test area without aphid damage. After picking aphids per plot selected 20 cotton, to investigate. Test results: From the first leaf emergence to the first leaf stage, the number of hundred aphids rose from 0 to 300 and finally to 2000, the rate of leaf curl rose to 3.1% and finally to 100%. Cotton seedlings at this time poor resistance, one hundred aphids in the 300 to 500 heads, the average roll leaf rate