茶皂素对茶尺蠖毒性作用初步研究

Toxicity Effect of Tea Saponin on Ectropis oblique

为研究茶皂素的生物活性及对昆虫作用机理,测定了茶皂素对茶尺蠖卵及幼虫的毒性作用。结果表明:施用浓度为0.1、0.2、0.4、0.8、1、2、4、8 mg/m L茶皂素后,卵孵化率分别为21.9%、16.2%、18.2%、11.7%、7.7%、6.2%、5.4%、5.9%,随着茶皂素浓度的提高,杀卵作用增强,高浓度茶皂素(?1 mg/m L)对茶尺蠖卵具有较强的杀卵作用。1、2、4、8 mg/m L茶皂素溶液处理茶尺蠖3龄幼虫并饲养5天后,无幼虫死亡,说明茶皂素对茶尺蠖3龄幼虫没有明显的触杀作用,对茶尺蠖的直接毒杀活性较弱。不同浓度的茶皂素对茶尺蠖3龄幼虫均有一定的拒食作用,随着浓度的增加,拒食效果增强,4、8 mg/m L的茶皂素拒食作用较强,分别达到80.0%、85.7%。取食过茶皂素的3龄、4龄、5龄幼虫虫体长度和重量与未取食的没有明显差异,饲喂8 mg/m L及以下浓度茶皂素的茶尺蠖生长发育均未受到明显影响。

To investigate the bioactive and the insecticidal mechanism of tea saponin on pest, toxicity effect oftea saponin on eggs and larvae of Ectropis oblique was determined. Toxicity test for eggs of E. oblique wasconducted at the concentration of 0.1, 0.2, 0.4, 0.8, 1, 2, 4, 8 mg/m L, respectively, and the corresponding hatchrate was 21.9%, 16.2%, 18.2%, 11.7%, 7.7%, 6.2%, 5.4%, 5.9%, respectively. This result indicated thattoxicity effect on eggs of E. oblique increased with the increase of tea saponin concentration. Leaves weredipped in tea saponin solution at the concentration of 1, 2, 4, 8 mg/m L, respectively, and then fed the thirdinstar larvae of E. oblique. The results showed that all the larvae survived, meaning that tea saponin had nosignificant toxicity on the third instar larvae of E. oblique. Antifeeding effect of tea saponin on the third instarlarvae was also determined. The results indicated that tea saponin had antifeeding effect on the third instarlarvae and the effect increased with the increase of the concentration. When the concentration of tea saponinwas at 4, 8 mg/m L, the antifeeding rate was 80.0%, 85.7%, respectively. Body length and weight of the third,fourth and fifth instar larvae which were treated by tea saponin had no significant difference compared with thatof the control group, indicating that feeding tea saponin at or below the concentration of 8 mg/m L had nosignificant effect on the growth and development of E. oblique.