用等效线评判稻田“桶混”农药联合作用方式的研究

Determination of joint action of pesticides mixed in barrels for paddy field with equivalent line

为了确定田间混用农药的联合作用方式,以田间防治效果作为农药剂量的生物效果,作单剂和混剂的剂量反应曲线,求得单剂、混剂获得相同防治效果的等效剂量。直角坐标的横轴和纵轴分别代表2种单剂的有效剂量,在坐标内分别标出单剂、混剂等效剂量的坐标点,连接单剂坐标点的直线为等效线,混剂坐标点如在等效线的下方,则为增效作用,在等效线上方,为拮抗作用,接近于等效线,为相加作用。室内测定结果表明吡虫啉-毒死蜱、噻嗪酮-毒死蜱和噻虫嗪-混灭威3个组合对褐飞虱有增效作用。田间试验结果表明吡虫啉-毒死蜱、噻嗪酮-毒死蜱和噻虫嗪-混灭威3个组合对稻飞虱有增效作用。说明用田间试验结果作等效线能够反映农药混用的联合作用效果。

To determine the type of joint action of pesticides mixed in barrels on field, the control efficiency of pesti- cides against pests were investigated in field test, the dose response curves of pesticides were drawn, and the equivalent dose to obtain the same control effects was found from these curves. The transverse and longitudinal axis of coordinate sys- tem represented separately effective dose of two pesticides, the coordinate points of the effective dose were marked in the coordinate system, and the straight line connecting coordinate points of two pesticides was called isobole. If the coordinate point of the mixture of two pesticides was below the isobole, the joint action of the mixture was synergism; otherwise, it was antagonism. If the corrdinate point was close to the isobole, the joint action was additive. Test in laboratory showed the joint action of three mixtures, imidacloprid-chlorpyrifos, buprofezin-chlorpyrifos and buprofezin-dimethacarb, was synergis- tic against brown plant hopper（ BPH）, and synergistic effects of the three combinations against rice planthopper in field was also observed. The results indicated the joint action of the mixture of pesticides could be determined with the isobole drawn based on to the field test.