巴东醉鱼草不同方法提取物的杀虫活性

为探讨巴东醉鱼草(Buddleja albiflora Hemsl.)的杀虫活性物质,以3龄粘虫(Mythimna separatea W.)为试虫,采用冷浸法、加热回流法、超声波法和渗漉法得到的巴东醉鱼草提取物应用小叶碟添加法进行毒力测定.结果表明:不同提取方法对茎的提取率均最低,叶的提取率最高.其中加热回流法对茎、叶、花的提取率最高,分别为5.76%、10.32%和9.29%,其次为超声波法,冷浸法最低.在浓度较大时,提取物对试虫的拒食活性较高;在浓度为相当于干样10 mg/mL时提取物对粘虫的生长发育影响较大,使试虫蜕皮不正常、最终出现畸形蛹或者是羽化不正常,其中加热回流法和超声波法的提取物效果明显.其中,叶的加热回流法提取物使试虫的56.67%由于生长发育不正常导致死亡;叶的超声波法提取物次之,为40%.

The Insecticidal Activity of Extracts with Different Methods from Buddleja albiflora Hemsl

To explore insecticidal components of the extractions from Buddleja albiflora Hemsl.,four extracting methods,cold-soaked extraction,reflux method,microwave-assisted extraction and percolation extraction,were adopted.The insecticidal activities of the extractions against the 3rd-instar larve of Mythimna separatea W.were tested by leaf disk method.The preliminary bioassay showed that the lowest rate for extraction is from stem part and leaf extract rate is the highest.The highest extraction rate of stem,leaves and flower of Buddleja albiflora Hemsl.was up to 5.76 percent,10.32 percent and 9.29 percent with the reflux method,followed by the microwave-assisted extraction.The cold-soaked extraction is the lowest.There are large numbers of abnormal moulting of the larvae,malformed pupae and no eclosion began to appear,with the dosage of 10 mg·mL^-1,the extraction with the methods of reflux method and microwave-assisted had obvious result.The abnormal mortality of extraction of leaves with reflux method against Mythimna separatea W.was up to 56.67% because of inhibiting of growth and development,and it was up to 40% with microw ave-as-sisted.