黄荆提取物对蚜虫的毒力及其与吡虫啉的联合毒力

采用浸渍法测定了黄荆二氯甲烷种子提取物、吡虫啉和氧乐果对苹果黄蚜、棉蚜和桃蚜的毒力，利用毛细管点滴法测定了黄荆二氯甲烷种子提取物与吡虫啉混配对棉蚜的联合毒力，采用皿内选择法测定了黄荆二氯甲烷种子提取物和吡虫啉等药剂对桃蚜的驱避效应.结果表明：黄荆二氯甲烷种子提取物对苹果黄蚜、棉蚜和桃蚜的LC₅₀分别为334.59、362.79和2685.80 mg·L^-1，对苹果黄蚜和棉蚜的杀虫毒力较高.黄荆二氯甲烷种子提取物与吡虫啉按1000 ∶1混用，其共毒系数可达177.45，增效作用显著.黄荆二氯甲烷种子提取物和吡虫啉对桃蚜均有明显的驱避活性，处理后24和48 h 对桃蚜的驱避率分别达55.75%、39.44 %和69.89%、65.43%.噻虫嗪和啶虫脒也有一定驱避活性，处理后24和48 h对桃蚜的驱避率达16.52%～33.68%.

Toxicity of Vitex negundo extract to aphids and its co-toxicity with imidacloprid.

In this paper, the toxicity of Vitex negundo seed dichloromethane extract, imidacloprid, and omethoate to Aphis citricola, Aphis gossypii, and Myzus persicae was determined by impregnation method, and the co-toxicity of the seed extract and imidacloprid to A. gossypii as well as the repellent effect of the extract and test insecticides to M. persicae were tested by topical application of capillary tube and by selection in culture dish, respectively. The results showed that the LC50 of V. negundo seed dichloromethane extract to A. citricola, A. gossypii, and M. persicae was 33459, 36279, and 26858 mg·L-1, respectively, indicating that V. negundo seed dichloromethane extract was highly toxic to A. citricola and A. gossypii. The co-toxicity coefficient of the seed extract and imidacloprid was 17745 when the mixture was in 1000 ∶〖KG-*2〗1, showing an obvious synergism. The repellent effect of V. negundo seed dichloromethane extract and imidacloprid to M. persicae was 5575% and 3944%, and 6989% and 6543% after treated for 24 and 48 hours, respectively, while that of thiamethoxam and acetamiprid to M. persicae was 1652%〖KG-*2〗-〖KG-*7〗3368% after treated for 24 and 48 hours.