Nauen Ralf, Smagghe Guy
Bayer CropScience AG, Research Insecticides, Biology, Alfred Nobel Str. 50, D-40789 Monheim, Germany.
Pest Manag Sci. 2006 May;62(5):379-82. doi: 10.1002/ps.1192.
The mode of action of the 2,4-diphenyl-1,3-oxazoline acaricide/insecticide etoxazole has been argued to be moulting inhibition, but experimental results supporting this hypothesis are lacking. This study investigated the effect of etoxazole on chitin biosynthesis in the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Etoxazole induced moulting defects in fall armyworm larvae similar, if not identical, to those caused by benzoylphenylureas, a well-known class of insecticidal chitin biosynthesis inhibitors. Furthermore, in contrast to untreated larvae, the chitin content in the integuments of larvae several days after treatment did not differ from that in freshly ecdysed individuals, thus suggesting strong chitin biosynthesis inhibition in vivo. A more detailed investigation of the inhibitory potential by incubating cultured integument pieces from larvae of S. frugiperda with [14C]N-acetyl-D-glucosamine, a radiolabelled chitin precursor, revealed I50 values of 2.95 and 0.071 microM for etoxazole and triflumuron respectively. The incorporation of radiolabel into potassium hydroxide-resistant material was inhibited by etoxazole in a dose-dependent manner. Based on these results, it is concluded that the acaricidal and insecticidal mode of action of etoxazole is chitin biosynthesis inhibition.
2,4-二苯基-1,3-恶唑啉杀螨剂/杀虫剂乙螨唑的作用模式一直被认为是抑制蜕皮，但缺乏支持这一假设的实验结果。本研究调查了乙螨唑对秋粘虫Spodoptera frugiperda (Smith)(鳞翅目：夜蛾科)几丁质生物合成的影响。乙螨唑在秋粘虫幼虫中诱导的蜕皮缺陷与苯甲酰脲类（一类著名的杀虫几丁质生物合成抑制剂）所引起的缺陷相似，即便不完全相同。此外，与未处理的幼虫相比，处理几天后幼虫体表的几丁质含量与刚蜕皮个体的几丁质含量没有差异，因此表明在体内强烈抑制几丁质生物合成。通过用放射性标记的几丁质前体[14C]N-乙酰-D-葡萄糖胺孵育秋粘虫幼虫的培养体表碎片，对抑制潜力进行更详细的研究，结果显示乙螨唑和氟虫脲的I50值分别为2.95和0.071 microM。乙螨唑以剂量依赖的方式抑制放射性标记掺入耐氢氧化钾物质中。基于这些结果，得出结论：乙螨唑的杀螨和杀虫作用模式是抑制几丁质生物合成。
