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 become major weeds in rangelands and pastures in North America. The biology and host specificity of Nephopterix divisella Duponchel (Lepidoptera: Pyralidae) was studied to evaluate its potential as a new biological control agent. This oligophagous, multivoltine stem borer is common on spurges such as E. characias in western and southwestern Europe. The results of no-choice feeding test with Ist instars, showed that the host range is restricted to plant species in the genus Euphorbia. Among them, feeding on E. milii Desmoulins and E. trigona Haworth, both ornamental plants, seems to bar chances for N. divisella to be selected as a leafy spurge biological control agent.