Effects of Total Ginsenosides on the Feeding Behavior and Two Enzymes Activities ofMythimna separata(Walker) Larvae

Abstract

Ginsenosides, the main effective components ofPanax ginsengC.A. Meyer andPanax quinquefoliusL., are important allelochemicals ofginseng. Although many studies have targeted the pharmacological, chemical, and clinical properties of ginsenosides, little is known about their ecological role inginsengpopulation adaptation and evolution. Pests rarely feed onginseng, and it is not known why. This study investigated the effects of total ginsenosides on feeding behavior and activities of acetylcholinesterase (AChE) and glutathione s-transferase (GST) inMythimna separata(Walker) larvae. The results showed that the total ginsenosides had significant antifeeding activity againstM. separatalarvae, determined by nonselective and selective antifeeding bioassays. In addition, the total ginsenosides had inhibitory effects on the activities of GST and AChE. The antifeeding ratio was the highest at 8 h, then decreased, and was the lowest at 16 h. Both GST and AChE activities decreased from 0 h to 48 h in all total ginsenosides treatments but increased at 72 h. Total ginsenosides had antifeeding activity againstM. separatalarvae and inhibitory effects on the activities of GST and AChE.