杠柳根皮粗提液对菜青虫生物活性的影响

试验研究杠柳根皮粗提液对菜青虫生物活性的影响测定结果表明,杠柳根皮乙醇提取液对菜青虫的生物活性影响高于杠柳根皮氯仿提取液和石油醚提取液,杠柳根皮乙醇提取液对菜青虫幼虫有较强的拒食作用和生长抑制作用,胃毒作用一般。用100倍液杠柳根皮乙醇提取液浸叶饲喂3龄、4龄、5龄菜青虫幼虫后24h其拒食率分别为94.9%、87.8%和92.7%,拒食后幼虫的化蛹率和蛹重均比对照显著降低。100倍液杠柳根皮乙醇提取液浸叶饲喂4龄菜青虫幼虫后24h和72h其生长抑制率分别为96.6%和82.5%。杠柳根皮乙醇提取液对菜青虫成虫产卵具有明显忌避作用,用50~100倍液杠柳根皮乙醇提取液喷雾处理油菜苗后2~4d其产卵忌避率达89.5%以上。

Effects of the crude extracts from Periploca sepium Bunge on the bioactivity of imported cabbage worm, Pieris rapae

The effects of the crude extracts from Periploca sepium Bunge on the bioactivity of imported cabbage worm were studied. The results show that the effect of ethanol extract on the bioactivity of imported cabbage worm is higher than that from chloroform and petroleum ether extracts. The main insecticidal actions of the ethanol extract include the strong antifeedant activity and the growth inhibition and certain action of stomach poisoning to the larvae of imported cabbage worm. Antifeeding rate with dilution of 100 times is 94.9%, 87.8% and 92.7% against the 3rd, 4th and 5th instar larvae respectively in no choice test, and the rates of growth inhibition on the 4th instar larvae are 96.6% and 82.5 % in 24h and 72h after treatment. The pupating and weight of pupaes are much lower than that of control. The crude extract has obvious detertory effect against the oviposition of imported cabbage worm. Oviposition deterrent rate is over 89.5 % in 2-4d after treatment when the seedlings are sprayed by ethanol extract with dilution of 50-100 times.