Developing Biological Control of Canada Thistle for Colorado’s Organic Producers Using the Host-Specific Fungus Puccinia punctiformis
Project Director
Dan W. Bean
Year Funded
2018
Award Number
2018-51300-28562
Funded Institution
Colorado Department of Agriculture
Grant Program
OREI (Organic Agriculture Research and Extension Initiative)
USDA NIFA Report
Project Overview
Canada thistle (Cirsium arvense) is an invasive, exotic, creeping perennial weed that is extremely difficult to control because fragmenting its deep, extensive root system through tillage simply propagates the weed. The rust fungus Puccinia punctiformis is a highly species-specific plant pathogen that can kill Canada thistle by invading its root system.
In this project, the Colorado Department of Agriculture worked with several organic farmers to optimize methods for applying P. punctiformis against Canada thistle, and to propagate the fungus for widespread use by organic farmers dealing with this weed.
Farmer Takeaways
(1) The rust fungus Puccinia punctiformis provides effective biological control of Canada thistle. Its effects build gradually over time, with substantial reduction in thistle stem density within one to four years.
(2) Methods for producing and using inoculum to introduce the fungus into a Canada thistle infestation are simple and accessible.
(3) This rust fungus is highly specific to Canada thistle and therefore safe to use.