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Improving lives by solving problems in agriculture and the environment

Leafy spurge in North America: case study

Leafy spurge (Euphorbia esula) is an invasive weed. It's known for its negative ecological and economic impact on rangelands across US and Canada. Its rapid growth and high regeneration rate allow it to easily outcompete native rangeland grasses and herbaceous plants with serious economic implications to livestock producers.

Flea beetle on leafy spurge

Leafy spurge in North America

Leafy spurge (Euphorbia esula L.) was first reported in the United States in 1827. By 1997, it was estimated to infest 2 million hectares across 35 states where it has numerous ill effects. This case study shows how we have successfully used biocontrol over a number of years to bring the plant under control.

CABI’s work on leafy spurge started in 1961 with a number of surveys on biological control agents in Western Europe. By 1997, it was estimated to infest 2 million hectares (ha) across 35 states. The invasive pest has a number of adverse economic and ecological effects. In rangeland, leafy spurge reduces livestock carrying capacity – decreasing earnings of livestock producers and increasing expenses related to control. In wildland, the weed reduces native species richness and cover, wildlife habitat productivity, and soil and water conservation benefits.

High density of Aphthona lacertosa beetles on leafy spurge

What we did

As a result of this work, 12 agents were screened and released in the US between 1970 and 1988. The biocontrol agents included five species of Aphthona flea beetles; of these, A. nigriscutis Foudras, and mixed populations of A. czwalinai (Weise) and A. lacertosa Rosenhauer proved to be the most successful. At the sites where flea beetles thrive and persist, leafy spurge is maintained at low densities.

leafy spurge with Aphthona flea beetles

Our achievements

On rangeland, a recovered grazing capacity valued at US$4.98 million (in 1997); this would support an increased 39,400 cattle, leading to additional production expenditures to the region’s input suppliers of about US$11.47 million. Together, the grazing capacity and increased earnings would add up to US$16.45 million (based on 1997 dollars).

On wildland, increased annual expenditures for wildlife associated recreation of about US$1.8 million and a US$785,000 annual increase in soil and water conservation benefits were estimated, generating a total US$2.6 million (based on 1997 dollars).