穗花马先蒿对小菜蛾的生物活性

研究了穗花马先蒿乙醇提取物对小菜蛾的触杀、拒食和抑制生长的作用.结果表明,穗花马先蒿乙醇提取物对小菜蛾3龄幼虫具有较高的的触杀和拒食活性,浸渍法处理对小菜蛾3龄幼虫72h的致死中浓度(LC50)为4.663 g/L,24、48h的拒食中浓度(AFC50)分别为8.238、9.185g/L;乙醇提取物对小菜蛾的生长发育抑制作用也明显,随施药剂量的增加,生长抑制率增大,化蛹率和羽化率降低,处理剂量为50.00g/L时,生长抑制率大于100%,化蛹率为41.11%,羽化率仅为12.22%.

Insecticidal Activity of Pedicularis spicata Pall against Plutella xylostella

Contacting, antifeeding and inhibition of growth and development on 3^th instar larvae of Plutella xylostella were determined. The results showed that ethanol extract possessed high effectiveness of contacting and antifeeding against 3^th instar larvae of Plutella xylostella. The LCso was 4.663 g/L by dipping method and the AFCso of complete antifeeding activity were 8.238, 9.185 g/L in 24, 48 h, respectively. Ethanol extracts also had strong effect on the growth and development of Plutella xylostella. The treated larvae showed big reduction on body weight, pupation rate, adult emerging rate and relative growth rate comparing with control. The higher the concentration of the extracts was, the more severe the effect on the pest was. When treated with concentration of 50.00 g/L, growth inhibition rate was more than 100%, with pupation rate and adult emerging rate were 41.11%, 12.22%.