3种生物源杀虫剂对杜仲梦尼夜蛾的毒力及防效

Toxicity and field efficacy of three biopesticides to Orthosia songi

针对专性为害杜仲的食叶害虫杜仲梦尼夜蛾(Orthosia songi Chen et Zhang)幼虫进行室内毒力测定,比较了3种生物源杀虫剂对其3龄和5龄幼虫的杀虫活性,并进行了林间药效测定和防治示范试验。结果显示:甲氨基阿维菌素苯甲酸盐(甲维盐)对3龄和5龄幼虫的LC50值分别为0.152 5和0.204 7μg/L,苦参碱的LC50值分别为65.306 0和124.735 8μg/L,印楝素的LC50值分别为165.871 7和257.749 0μg/L。林间药效测定结果显示5.7%甲维盐微乳剂300万倍液防治效果最好,7d后校正死亡率达91.34%。防治示范试验表明,5.7%甲维盐微乳剂75 000倍液防治效果达95.69%,显著高于0.3%苦参碱水剂750倍液的防治效果(80.28%),且药剂成本7.5元/hm2,仅为后者的1.9%。

Orthosia songi Chen et Zhang is a monophagous insect specifically feeding on Eucommia ulrnoides leav- es. The toxicity and effectiveness of 3 biopesticides against 3rd and 5th instar larvae of O. songi were tested. Field trails and demonstration test were conducted to determine the optimal insecticide and control technique. Laborato- ry toxicity experiments showed that the LCs0 values of matrine, azadirachtin and emamectin benzoate against 3rd and 5th instars larva were 65. 306 0 and 124. 735 8μg/L, 165. 871 7μg/L and 257. 749 0 μg/L, 0. 152 5 μg/L and 0. 204 7 μg/L, respectively. Field trials demonstrated that the corrected mortality was 91.34% spayed by 3 000 000 times dilution of 5.7% emamectin benzoate. Demonstration test indicated that control efficacy of 75 000 times di- lution of 5.7% emamectin benzoate was 95.69%, significantly higher than that of 0.3% matrine diluted 750 times which was used in practice. The cost of 5.7% emamectin benzoate was RMB 7.5 yuan/hm^2, approximately 1.9% that of matrine.