平卧川牛漆甾酮是紫背金盘中的主要植物蜕皮甾类,在筋骨草属植物中普遍存在.试验结果表明,用50mg/L平卧川牛漆甾酮处理小菜蛾卵,其孵化受到抑制,总孵化率为94.7%,显著低于对照的100%孵化.平卧川牛漆甾酮对幼虫具有弱的毒杀活性和良好的拒食活性,且与浓度相关.小菜蛾的生长发育也受平卧川牛漆甾酮的影响.用高于50 mg/L浓度处理幼虫,其生长受抑及蛾的产卵量下降,而较低浓度处理则有利于幼虫生长,卵量提高.这种双重作用可能是由于平卧川牛漆甾酮的激素活性和拒食活性的作用结果,后者导致昆虫营养不良.处理幼虫后,试虫的化蛹和羽化受阻.小菜蛾对平卧川牛漆甾酮比20-羟基蜕皮酮更敏感.%Cyasterone is the main phytoecdysteroid component from cultured plants of Ajuga nipponensis, and common in other Ajuga species. Results showed that when treated with 50 mg/L cyasterone, the egg hatching of dia mondback moth was retarded. The total percentage of eggs hatched in treatment was 94.7 %, significantly less than that in control, which was 100%. Low toxicity and good antifeeding activity to the 3rd instar larvae were exhibited,which are dependent upon concentration. The growth and development of diamondback moth were affected by cyaster one. It was found that, at concentrations higher than 50 mg/L cyasterone, the larval growth and egg production were inhibited; while promoted at lower concentrations. This dual role of cyasterone might be attributed to its hormonal ac tivity and antifeeding activity, which resulted in poor nutrition. The pupation and eclosion were hindered by treatment of larvae. This insect species was more susceptible to cyasterone than 20-hydroxyecdysone.
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