二斑叶螨对240g/L螺螨酯悬浮剂的抗药性预测

[目的]预测二斑叶螨对螺螨酯(240 g/L SC)产生抗药性的速度,指导合理用药。[方法]以选择压力为杀死种群50%～60%的剂量,对二斑叶螨敏感种群进行室内汰选,每隔5代用浸叶碟法和叶片残毒法对种群进行测定,求得毒力回归方程。[结果]经过25代汰选,二斑叶螨的卵对螺螨酯抗性指数仅上升至1.28倍,并未产生明显抗性。汰选至35代,对幼螨的LC50值(制剂量)由15.1252 mg/L升高至127.2624 mg/L,获得抗性指数8.41倍的抗性种群。[结论]在室内汰选35代后,二斑叶螨的幼螨虫态对240 g/L螺螨酯SC已产生明显抗药性。

The Prediction of Spirodiclofen 240 g/L SC Resistance in Two-spotted Spider Mite

The resistance velocity of Tetranychus urticae Koch(T.urticae) to spirodiclofen 240 g/L SC was monitored to direct to use acaricides in a resonable way.[Methods] Selected a susceptible strain of T.urticae under pressure of killing about 50-60% population with spirodiclofen 240 g/L SC.The population was tested every five generations by using both leaf disk dip and leaf residue methods,and LC-P line was obtained.[Results] After 25 selection cycles with spirodiclofen 240 g/L SC,resistance ratio of T.urticae eggs only rose to 1.28 times.The egg stage remained far more susceptible to spirodiclofen 240 g/L SC.On the other hand,LC50 value of larvaes increased?from 15.1252?to 127.2624 mg/L when up to the 35th selection cycles Obtaining a strain with a resistance ratio of 8.41,determined on larval stage of T.urticae.[Conclusions] After the 35th selection cycles,more obvious resistance of larvaes has already formed.