Distribution of the chemotypes ofWithania somnifera in some areas of Israel: Feeding studies withSpodoptera littoralis larvae and chemical examination of withanolide content

The geographical distribution of the chemotypes ofWithania somnifera Dun. (Solanaceae) in Israel was re-investigated. In the distribution area of chemotype II (major steroidal constituent, withanolide D), plants of chemotype III (major steroidal constituent, withanolide E) were also found. The antifeedant properties forSpodoptera littoralis larvae of leaves ofW. somnifera populations belonging to chemotype III are due to the presence of withanolide E and may be used, as a supplement to chemical analysis, to differentiate between chemotype III and other chemotypes ofW. somnifera.