Managing Invasive Leafy Spurge, Euphorbia esula, at the Minnesota Landscape Arboretum. Sean Bowerman

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1 Managing Invasive Leafy Spurge, Euphorbia esula, at the Minnesota Landscape Arboretum Sean Bowerman

2 First appeared in U.S. in Massachusetts in 1827 Mature plants are 1-3 feet tall Broad leaves; 4 inches long; alternate pattern Greenish-yellow bracts; present late spring/early summer Milky sap Extensive root system; most abundant in top foot of soil Leafy Spurge - Euphorbia esula

3 Arrives early spring HUGE nutrient reserve; allows survival from long droughts and most Integrated Pest Management (IPM) strategies Root system may extend upwards of 20 feet deep Seeds can eject up to 15 feet from plant; float on water According to the Montana Weed Control Association, coverage doubled every decade for past 100 years; can reduce natural herb coverage by 75% Infestation Wyoming, Montana, Dakotas Cost agricultural producers and tax payers $144 million annually in production costs, control expenses, and loss of native plants and wildlife diversity Leafy Spurge Struggles

4 National Coverage of Euphorbia esula According to the Minnesota Department of Agriculture, Leafy Spurge is on the Control List: Species on this list must be controlled, meaning efforts must be made to prevent the spread, maturation and dispersal of any propagating parts, thereby reducing established populations and preventing reproduction and spread as required by Minnesota Statutes, Section (Minnesota Noxious Weeds).

5 1. Locate populations of Euphorbia esula around the Arboretum grounds 2. Establish a database using the Arboretum GPS to use to track and manage populations for the long-term future 3. Determine possible avenues for treatment of the Euphorbia esula Objectives

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8 According to the University of California s statewide program, IPM is an ecosystem-based strategy that focuses on the long-term prevention of pests or their damage through a combination of techniques Strategies include: Biological control Cultural control Mechanical/physical control Chemical control What is Integrated Pest Management?

9 Use of natural enemies Striped Flea Beetle (Phyllotreta stirolata) Black Beetle (Aphthona lacertosa) Released in 2006; June 2007 Use of competitors Indian Grass (Sorghastrum nutans) Lady s Mantle (Alchemilla mollis) Biological Control

10 Practices that reduce establishment, repro duction, dispersal, a nd survival of pest Burning (Boy Scout Hill 3x; last burn May 2008) Mowing (Overflow Parking) Cultural Control

11 Practices that directly kill/block or make an unsuitable environment for the pest Animal traps/barriers Mulching flower beds Prevents weed growth Steam sterilization Kills microorganisms and spores Mechanical/Physical Control

12 Use of pesticides in combination with other methods for long-term, noticeable effects Tordon (Picloram), Banvel (Dicamba), and 2-4D Control broadleafs, not grasses Plateau (Imazapic) Limited broadleaf control, safe for trees and shrubs; destroys grass at high quantities Paramount (Quinclorac) Limited broadleaf control, safe around nearly all trees, shrubs, and grasses Roundup Destroys everything Chemical Control

13 General rule: For every year of establishment, two years of treatment for complete control Treat like fire: Tackle small patches first to prevent establishment; work along edge of larger populations, slowly moving to center Noninvasive Alternatives Indian Grass White-flowered baby s breath euphorbia (Euphorbia corollata) Annual flowering tobacco hybrids (Nicotiana nikki hybrids) Natural Enemies Leafy Spurge Hawkmoth (Hyles euphorbiae) Stem-Boring Beetle (Oberea erythrocephala) Blue-black Flea Beetle (Aphthona czwalinae) Chemicals Paramount relatively safe around everything Cultural Control Sheep and goats Recommendations

14 Agriculture and Natural Resources, University of California. (Ed.). (2016). What is Integrated Pest Management (IPM)? Retrieved August 04, 2016, from Arboretum Staff: Dan Miller, Richard DeVres, Rich Gjertson Chace, T. D. (2013). How to eradicate invasive plants. Portland: Timber Press. Dickinson, R., & Royer, F. (2014). Weeds of North America. Chicago, IL: University of Chicago Press. Leafy Spurge. (2016). Retrieved August 04, 2016, from spurge/ Minnesota Noxious Weeds. (2016, August 16). Retrieved August 16, 2016, from st.aspx United States, Department of Agriculture, National Resources Conservation Service. (2016, August 16). Plants Database. Retrieved August 16, 2016, from Wax, L. M., Fawcett, R. S., & Isely, D., etc. (1981). Weeds of the North Central States(Bulletin 772). Urbana, IL: University of Illinois at Urbana-Champaign, College of Agriculture, Agricultural Experiment Station. Sources