Effects of selected Larix laricina terpenoids on Lymantria dispar (Lepidoptera: Lymantriidae) development and behavior

Abstract

The effects of selected terpenoids of tamarack, Larix laricina (Du Roi) K. Koch, on the growth and development of gypsy moth, Lymantria dispar (L.), were studied in laboratory trials. Second instars were fed standard artificial diet disks supplemented with a known amount of diterpene acid, monoterpene, or control. Diterpene acids had strong, dose-dependent antifeedant effects on gypsy moth larvae. Monoterpenes had less pronounced and more varied effects on gypsy moth larval performance. High concentrations of monoterpenes did not affect gypsy moth growth. However, low concentrations of some monoterpenes that are present in tamarack in small amounts (<10% total monoterpenes) appeared to increase gypsy moth growth. Some monoterpenes caused slightly longer development time.