Biological Control of Leafy Spurge (Euphorbia esula) with Aphthona spp. along Railroad Right-of-Ways

Leafy spurge (Euphorbia esula) along long distances of railroad right-of-ways is often treated with the least expensive herbicides available that only control top growth. The objective of this research was to evaluate flea beetles, Aphthona nigriscutis and a mixed population of A. czwalinae and A. lacertosa, for establishment and potential to reduce leafy spurge infestations along railroad right-of-ways. In separate experiments, both Aphthona species established the first year following release, and the rate of spread was similar regardless of the initial number released. Aphthona nigriscutis reduced leafy spurge approximately 65% up to 16 m from the release point by 3 to 5 yr after release. The mixed population of A. czwalinae and A. lacertosa reduced leafy spurge density over 95% within 4 yr of release. Biological control is an alternative to chemical control for leafy spurge along railroad right-of-ways, and establishment at these sites could facilitate biological control agent movement into remote areas.