Leafy spurge is difficult to kill because it has a pervasive root system that seems to block the absorption of herbicides. Natural enemies of leafy spurge were evaluated in Europe and in quarantine station in the U.S. before being released. Furthermore ARS scientists checked whether insects would attack crop and pasture plants including Corn and Alfalfa. They also studied these insects effect on native Euphorbia species. Because the gall that the midge creates prevents the plant from flowering and producing seed.
Aphids rears the insects in insectaries.
It takes about 3 or 4 years before the insect populations can reach a density large enough to begin having a controlling affect on the plant. Because the native species such as poinsettia are not a threat to the pastures and range lands.