Back to Research & Demonstration

Understanding and manipulating leafy spurge populations with cattle grazing and biological control

 

Project Details

  • Project Lead: Jane Thornton, retired (Manitoba Agriculture) & Mae Elsinger (Agriculture and Agri-Food Canada)

  • Collaborators: Bev Dunlop (Agriculture and Agri-Food Canada)

  • Years: 2015-2021

  • Project Status: Complete

  • Funding & In-Kind Support: Canadian Agricultural Partnership, Growing Forward II, Agriculture & Agri-Food Canada

  • Location: First Street Pasture

  • Scope: Case Study

  • Keywords: Weed Management

Approach

Cattle were taught to increase the amount of leafy spurge in their diet to increase cattle tolerance of foraging among spurge plants with the potential of impacting the spurge itself. Damage to spurge from cattle and other biocontrols including spurge leaf tier moths, spurge gall midges, spurge flea beetles, and leafy spurge hawkmoths was monitored.

Leafy spurge abundance was surveyed throughout the pasture to understand the extent of the infestation.

Effect of grazing versus not grazing was compared in relation to abundance and health of leafy spurge and leafy spurge flea beetle populations.

Key Findings

Teaching Cattle to Eat Leafy Spurge:

  • Trained cattle are more likely to graze within leafy spurge patches

  • Cattle grazing and trampling impacted a relatively small number of stems compared to overall spurge population

Leafy Spurge Flea Beetles:

  • The leafy spurge flea beetles and their larvae appear to be playing an essential role in reducing leafy spurge

  • The grazed vs. ungrazed study on abundance and health of spurge flea beetles and spurge was poorly designed and no conclusions were available.

Other Biological Controls:

  • Natural enemies, such as spurge leaf tier moths (Lobesia euphorbiana) and spurge gall midges (Spurgia esulae) have been found to impact many of the spurge stems in the pastures.

Accumulated percentages of leafy spurge stems visibly damaged by grazing, trampling, spurge leaf tier moth nests, spurge gall midge nests, and unknown damages.

Distribution of 1229 individual samples of leafy spurge stem density counts, with critical thresholds or zones marked, to illustrate level of control of spurge at this pasture by natural enemies, primarily spurge flea beetles.

Industry Resources:

Related Projects at MBFI: