Coleophora klimeschiellaToll, whose larvae feed as case bearers on the foliage of Russian thistle,Salsola ibericaSennen and Pau, was introduced into quarantine in the U. S. in 1975. Detailed oviposition and larval feeding tests were conducted during 1975–76 on closely related plants and crop and ornamental species. Although eggs were laid on several non-host plant species, the insect was not able to complete larval development on any plant tested except Russian thistle.Coleophora klimeschiellahas been approved for field release by state and federal agencies.