BIOLOGY AND HOST PREFERENCE OF NEPHOPTERYX DIVISELLA (LEPIDOPTERA, PYRALIDAE) - CANDIDATE AGENT FOR BIOLOGICAL-CONTROL OF LEAFY SPURGE COMPLEX IN NORTH-AMERICA

Euphorbia osula L. (Euphorbiaceae) is a complex of species that has be come major weeds in rangelands and pastures in North America. The biol ogy and host specificity of Nephopterix divisella Duponchel (Lepidopte ra: Pyralidae) was studied to evaluate its potential as a new biologic al control agent. This oligophagous, multivoltine stem borer is common on spurges such as E. characias in western and southwestern Europe. T he results of no-choice feeding test with Ist instars, showed that the host range is restricted to plant species in the genus Euphorbia. Amo ng them, feeding on E. milii Desmoulins and E. trigona Haworth, both o rnamental plants, seems to bar chances for N. divisella to be selected as a leafy spurge biological control agent.