雷公藤根皮提取物对茭白二化螟的生物活性

Bioactivity of root bark crude extracts of Tripterygium wilfordii Hook to striped stem borer, Chilo suppressalis Walker on Zizania caduciflora

研究了雷公藤根皮乙醇提取物对茭白二化螟的生物活性 ,结果表明 ,提取物对二化螟幼虫有较强的拒食作用、生长发育抑制作用、毒杀作用和内吸毒力。对 2龄 1日幼虫选择性与非选择性的拒食中浓度 (AFC50 )分别为111 5 7μg/mL和 14 4 2 8μg/mL ,生长发育的抑制中浓度 (EC50 )为 134 39μg/mL。内吸毒杀作用在 16 0 0 μg/mL浓度下能达到 90 %以上 ,胃毒作用在 80 0 μg/mL下 ,处理 5d后的死亡率为 73 71% ,对二化螟蚁螟的触杀作用不明显 ,对天敌螟黄足绒茧蜂安全。

Laboratory bioassay was conducted to evaluate the efficacy of Tripterygium wilfordii root bark crude extracts against striped stem borer (SSB), Chilo suppressalis on Zizania caduciflora. The results showed that the extracts had obvious stomachic toxicity, systemic action, antifeedent and growth inbibition activity on SSB larvae. In choice tests and non-choice tests, the medium antifeeeding concentration (AFC 50 ) of the extracts to 2nd instar SSB larvae were 111.57 μg/mL and 144.28 μg/mL, respectively. The medium growth inhibition concentration (EC 50 ) was 134.39 μg/mL. In the systemic experiment over 90% larvae were killed treated with 1 600 μg/mL, and 73.71% larvae died treated with 800 μg/mL after 5 days when fed with the extracts. The extracts presented unremarkable insecticidal activity to the newly-hatched larvae and was safe for Apanteles flavipes adults, the parasitoid of SSB larvae.