Insecticidal activity of Juglans regia extracts against Tetranychus cinnabarinus and their effects on relative enzymes activity in Tetranychus cinnabarinus

Abstract

The experiment was conducted to determine the insecticidal activity of three different extracts from walnut green husk against Tetranychus cinnabarinus. The results showed that the female insect mortality was 83.44 % at 24 h after exposed in the petroleum ether extract(1 mg·mL-1) from walnut green husk, which was significantly higher than that in the chloroform and methanol extracts (P < 0.05) . After parted and purified by extracting and chromatography, it was found that the acaricidal activity of petroleum ether part from crude extracts was significantly more than the methanol part in the concentration of 1 mg·mL-1, and the female insect mortality reached 84.39 % at 24 h after exposed in the petroleum ether part. There were 19 parts gained from petroleum ether part by chromatography, and the insecticidal activity of 4 parts (6th, 7th, 13th, 17th parts) was higher than other parts, which mortality to female insects was more than 60 %. And the purity of 6th part has been above 90 % by HPLC. After detailed gradient detection, it was found that the extraction rate of 6th part from crude extracts was 6.34% in the concentration of 10mg·mL-1, and the female insect mortality was 98.45 %. On the other hand, the effect of 6th part on relative enzymes activity in Tetranychus cinnabarinus was also researched by colorimetric method. The results showed that the activity of AchE and Na+, K+-ATPase in Tetranychus cinnabarinus were 0.47 and 0.62 times as the control after the exposure in the concentration of 10 mg·mL-1 at 8 hours. © 2012 Springer-Verlag GmbH.