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室内毒力测定和田间药效试验证明 ,氧化乐果等 9种药剂对银杏大蚕蛾 1、2龄幼虫具有良好的防效。不同药剂对银杏大蚕蛾幼虫的 LD5 0 不同 ,以氧化乐果的毒力最弱 ,其对 1龄幼虫的 LD5 0 为 7.93× 1 0 - 4 ,对 2龄幼虫的 LD5 0 为 1 .92 6× 1 0 - 3;以贝塔 -氟氯氰菊酯的毒力最强 ,其对 1龄幼虫的 LD5 0 为 5.3 98× 1 0 - 8,相对毒力为 1 4690 .63 ,对 2龄幼虫的 LD5 0 为 9.0 73× 1 0 - 8,相对毒力为 2 1 2 3 4 .84。同一种药剂随着虫龄的增大其毒力有所降低 ,不同药剂毒力降低的倍数不同 ,降低倍数在 1 .3 3～ 1 4.75之间 ,毒力曲线可以作为相对敏感基线。田间防治银杏大蚕蛾 1～ 3龄幼虫第 1天的药效为 50 %～ 90 %,第 3天在 60 %～ 1 0 0 %之间 ,第 7天在 80 %～ 1 0 0 %之间 ,其中有机磷类农药的药效较好 ,为 65%～ 90 %;菊酯类农药的药效最好 ,为 80 %～1 0 0 %。
Laboratory tests of toxicity and field efficacy showed that 9 agents such as omethoate had good effects on the 1st and 2nd instar larvae of the giant silk moth. Different agents on the Ginkgo biloba larvae LD50 different from the weakest omethoate virulence, the first instar larvae of LD5 0 7.93 × 10-4, the second instar larvae of LD5 0 was 1.92 6 × 10-3. The virulence of beta-cyfluthrin was the strongest. The LD50 of the first-instar larvae was 5.398 × 10-8, the relative virulence was 14,690.63, and the LD50 of the second-instar larvae 9.073 × 10 ~ 8, relative toxicity was 2 1 2 3 4 .84. The virulence of the same agent decreased with increasing age of insects, and the multiples of the virulence of different agents decreased by a factor of 1.3 to 1.475. The virulence curve could be used as a relatively sensitive baseline. In the field, the efficacy of the 1st to 3rd instar larvae on the 1st day was 50% -90% on the 1st day, between 60% and 100% on the 3rd day, and between 80% and 100% on the 7th day , Of which organic phosphorus pesticide efficacy is good, 65% to 90%; pyrethroid pesticide efficacy of the best, 80% ~ 100%.