防治甘草萤叶甲生物源农药筛选及其对生物多样性的影响

Screening of biogenic pesticides to Diorhbda tarsalis and effects of biogenic pesticides to bio-diversity

为了筛选出防治甘草萤叶甲Diorhbda tarsalis Weise的生物药剂,采用多种生物源药剂,通过室内、田间试验,进行综合分析。室内毒力测定结果表明,甘草萤叶甲对0.5%黎芦碱SL的敏感性最高,LD50为0.139mg/L,0.3%印楝素EC、L2、1%苦参碱SL、L1依次递减,LD50分别为0.457,1.352,2.014和2.251mg/L,均高于其他药剂。田间防效结果表明,黎芦碱药后21d对甘草萤叶甲的防效最高,为100%,苦参碱、印楝素次之,均为86.67%,L2、L1的分别为66.67%和40%;对非靶标害虫小绿叶蝉也有较好的控制作用,药后21d防效L1较低,为56.67%,其他防效均高于68.89%;对田间天敌多异瓢虫和中华草蛉的安全性,除黎芦碱外,印楝素、苦参碱、L2、L1均较好,药后21d校正虫口减退率最高为57.14%;另外,苦参碱药后各期生物多样性指数平均最高,为2.93,印楝素次之,为2.88,藜芦碱、L1、L2依次递减,分别为2.45,2.43和2.07。因此,印楝素、苦参碱是防治甘草萤叶甲的理想药剂。

In order to screen pesticides against Diorhbda tarsalis Weise,toxicity of the pesticides was assayed by indoor and field experiments. The results of indoor toxicity showed that the sensitivity of D. tarsalis to vertrine 0.5% （SL） is the highest; the LD 50 value is 0.139 mg/L,the followings are azadirachtin 0.3% （EC）,L2,matrine 1% （SL）,and L1; the LD 50 values of these pesticides are 0.457,1.352,2.014 and 2.251 mg/L respectively. Those are all higher than that of other biogenic pesticides and chemical pesticides. The results of field efficacy showed 100% control effect of vertrine against D. tarsalis in 21 days,while the effect of matrine and azadirachtin are both 86.67%. The control effect of L2 and L1 are only 66.67% and 40%,respectively. In addition,above pesticides has distinct control effects to non-target pest Empoasca spp. as well. Those control effects in 21 days,except for L1,are all higher than 68.89%. Azadirachtin,matrine,L2,and L1 are safe to narural enemies Hippodamia variegate and Chrysopa sinica; the highest correction reduced rate is 57.14%. What is more,these pesticides has minor effect on bio-diversity in ecosystem. The average bio-diversity index of matrine in all time is 2.93,that of azadirachtin,L1,L2,and vertrine is 2.88,2.45,2.43,and 2.07,respectively. Therefore,azadirachtin and matrine are considered to be ideal pesticides to control D. tarsalis.