三种杀螨剂对山楂叶螨的毒力评价
Toxicity evaluation of three acaricides against hawthorn spider mite Amphitetranychus viennensis Zacher

为筛选出高效防治山楂叶螨Amphitetranychus viennensis Zacher的杀螨剂，利用玻片浸渍法和叶片残毒法测定了3种杀螨剂对其3种螨态的室内毒力，并对不同浓度杀螨剂的田间防效进行了测定。结果表明：240 g/L螺螨酯、110 g/L乙螨唑和43%联苯肼酯中仅联苯肼酯对山楂叶螨雌成螨有毒力，其LC50为37.65 mg/L；3种杀螨剂均能毒杀卵及幼螨，毒力大小依次为乙螨唑 > 联苯肼酯 > 螺螨酯；同一杀螨剂对幼螨的毒力均高于对卵的毒力。240 g/L螺螨酯和110 g/L乙螨唑对山楂叶螨的总体防效较好，除螺螨酯4 000倍液处理的防效在药后30 d达到最大97.11%外，其余各处理均在药后15 d达到最大，防效为88.76%~96.14%；但二者速效性较差，药后1~7 d防效均低于对照；而螺螨酯4 000、5 000倍液处理及乙螨唑5 000倍液处理的持效性较好，药后30 d防效仍有97.11%、90.90%和93.06%，均显著高于对照。43%联苯肼酯对山楂叶螨的总体防效在3种杀螨剂中最高，其1 800、2 500倍液处理分别在药后7 d和3 d时防效达到最大99.79%和98.64%；1~7 d防效为97.45%~99.79%，显著高于其余杀螨剂和对照；30 d时防效分别达98.14%和96.19%，速效性和持效性均较好。表明螺螨酯和乙螨唑对山楂叶螨的持效性较好，联苯肼酯则有良好的速效性和持效性，可以按照其不同特点推广应用。
In order to obtain effective insecticides to control Amphitetranychus viennensis Zacher, the toxicity of three acaricides were evaluated for three mite developmental stages and filed control efficacy by using slide-dip and leaf residue methods. The results showed that 43% bifenazate SC had toxicity to female adults among the three acaricides tested, with a LC50 value of 37.65 mg/L. The three acaricides all had high toxicity to eggs and larvae of the mites, and the toxicities of different acaricides to eggs and larvae were:etoxazole > bifenazate > spirodiclofen. The toxicity of the same acaricide to larvae was all higher than to eggs. The field tests showed that 240 g/L spirodiclofen SC and 110 g/L etoxazole SC all had good control efficacy to the mites, except 4 000 times dilution of spirodiclofen; the other treatments reached the highest control efficacy (88.76%-96.14%) after application for 15 days, but they showed poor available effect to the mites, their control effects after 1-7 days were lower than that of chemical control. 4 000 and 5 000 times dilution of 240 g/L spirodiclofen SC and 5 000 times dilution of 110 g/L etoxazole SC had good lasting validity period, their control efficacy still reached 97.11%, 90.90% and 93.06%, respectively, after application for 30 days, and significantly higher than that of chemical control. 43% bifenazate SC had the highest control effect among the three acaricides to the mites; the control effects of 1 800 and 2 500 times dilution treatments reached the highest after application for seven and three days (99.79% and 98.64%), showing excellent available effects and good lasting validity period. The control effects after 1-7 days (97.45%-99.79%) were all higher than those of other acaricides, with a control effect of 98.14% and 96.19%, respectively, after application for 30 days, significantly higher than that of control. These results indicated that spirodiclofen and