棉花叶螨对三氯杀螨醇和氧乐果的抗性动态

Resistance dynamics of cotton spider mites to dicofol and omethoate

对棉花叶螨（优势种朱砂叶螨）抗三氯杀螨醇和氧乐果的系统监测表明，棉田化防前期是当年棉花叶螨抗性最低点，大面积化防后抗性水平明显上升。化防停止后至下年春季，抗性呈下降趋势，反映在系统监测动态上，棉花叶螨抗性水平曲折性上升。对三氯杀螨醇和氧乐果的抗性分别由1986年的5．28～6．65倍和9．24～11．26倍上升到1992年的8．55～15．57倍和19．23～28．48倍。

A survey of dicofol and omethoate resistance in spider mices (Tetranychus urticae koch)in Henan Province was conducted by slide soaking method in 1986-1992. Their resistant levels were detected every year in early and late cotton growth stages. Date from the 7 year detections showed that the. resistance in late spring was the lowest point of one ycar, because of selective press of insecticides, it inereased rapidly and reached the highest level for the year in late summer. After stopped spraying of insectides, it declined gradually until next spring. The resistance dynamic curve by systematic monitoring increased tortuously, but for the same periods along the year series, they were all exponential curves. In 1986- 1992, the dicofol resistance of spider mite incr.ased from 5. 28-6.65 to 8-55 -15.57 fold, and omethoate resistance changed from 9.24-11 .26 to 19.23-28-48.