Robert (Bob) Parker and Rick Boydston, PhD
PNW 133 | Revised April 2020

Summary

A member of the Caltrop family, this weed produces woody fruits that always land with one sharp spine pointed upward. Spines injure hooves, feet, and vehicle tires. A toxin from the plant may be linked to photosensitization in sheep, leading to bighead. Cultural, and biological controls are discussed. Chemical pesticides were legal at time of printing.

About the authors

Rick Boydston, PhD
Agronomist
USDA-ARS, Irrigated Agriculture Research and Extension Center

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