Abstract
A method is described for mass-rearing Chrysocharis laricinellae (Ratzeburg) on larch casebearer larvae, employing a water culture system for tamarack. The rearing unit accommodates a well-defined episode (limited contact) in the interaction with its host. The yield is about 100 healthy parasites obtained from 300 cases, when the initial inoculum was 15 parasite females.