杀虫剂混合使用的增效作用评判分析

用共毒因子重新评价共毒系数大于100的281个混配组合,发现有29.18%的混配组合没有增效作用。根据单剂的LC-P线和共毒因子公式,求出混剂的期望死亡率和"相加作用区间"(期望死亡率±20%期望死亡率),根据混剂的实测死亡率求出95%置信区间,画出期望LC-P线及"相加作用区间"和实测LC-P线及"95%置信区间",发现当共毒系数大于100、共毒因子小于20时,实测LC-P线和期望LC-P线彼此交缠,期望LC-P线的"相加作用区间"和实测LC-P线的"95%置信区间"能高度重叠,表明两条LC-P线之间没有毒力差异;当共毒系数大于100、共毒因子大于20,或者共毒系数小于100、共毒因子小于-20时,实测LC-P线的"95%置信区间"和期望LC-P线的"相加作用区间"只有少量重叠或完全不重叠,体现出了实测LC-P线和期望LC-P线对供试害虫的毒力差异。因此,为了获得有稳定增效作用的混配组合,共毒系数须大于100,同时共毒因子也要大于20。

Evaluation of the Synergism of Mixtures of Pesticides

Joint actions of 281 mixtures of pesticides whose co-toxicity coefficients were over 100 were recalculated with the formula of co-toxicity factor and the results showed that 29.18% of the mixtures had no synergism. According to the LC-P line of each of insecticide in the mixture and the formula of co-toxicity factor,several expected mortality and the region of additive action (expected mortality±20% expected mortality) were calculated,and according to observed mortality of mixture,the 95% confidence interval was calculated,LC-P line of expected mortality with the region of additive action and LC-P line of observed mortality with the 95% confidence interval were drawn,it was found that there was overlap between the region of additive action and 95% confidence interval and two lines crossed each other when co-toxicity coefficient was more than 100 and the co-toxicity factor was less than 20,which meant there was no significant differences between expected mortality and observed mortality,and that there was on or a few overlap between the region of additive action and 95% confidence interval when co-toxicity coefficient was more than 100 and the co-toxicity factor was more than 20 or co-toxicity coefficient was less than 100 and the co-toxicity factor was less than 20,which meant there was significant differences between expected mortality and observed mortality.So,in order to obtain a synergistic mixture of pesticides to pest,the co-toxicity coefficient must be more than 100 and the co-toxicity factor was more than 20,too.