Integrating thistle rust into weed management of Canada thistle

View the project final report

Commodities

• Agronomic: barley, other, peas (field, cowpeas), safflower, triticale, wheat

Practices

• Animal Production: rangeland/pasture management
• Crop Production: biological inoculants, conservation tillage, cover crops, crop rotation, cropping systems, fallow, intercropping, multiple cropping, no-till, strip tillage, stubble mulching
• Education and Training: demonstration, extension, networking, on-farm/ranch research, other, workshop
• Natural Resources/Environment: biodiversity, habitat enhancement, strip cropping
• Pest Management: biological control, competition, cultivation, cultural control, disease vectors, economic threshold, field monitoring/scouting, integrated pest management, physical control, prevention, weed ecology
• Production Systems: agroecosystems, dryland farming, organic agriculture, organic certification, transitioning to organic
• Soil Management: green manures, organic matter
• Sustainable Communities: local and regional food systems, quality of life, sustainability measures

Cirsium arvense (L.) Scop. (Canada thistle) is an aggressive perennial weed which threatens sustainable crop production. Organic producers throughout Montana and across the Western region have expressed the need for the development of integrated Canada thistle management programs which include mechanical, cultural, and biological control tactics. The fungal pathogen, Puccinia punctiformis (thistle rust), is a highly selective Canada thistle parasite that has the potential to aid in the suppression of Canada thistle when integrated with other agronomic management tactics. This research and education project will (1) explore methods to integrate thistle rust into tillage practices and cropping rotations to reduce the spread and impact of Canada thistle in organic settings, and (2) convey the generated information to organic and conventional farmers to facilitate the development of integrated weed management practices.

In this study, we evaluate in certified organic farms and experimental plots: (1) the impact of conventional and reduced tillage practices on the establishment and spread of thistle rust in Canada thistle populations, and (2) Canada thistle growth and spread within competitive cropping rotations. Research results have been used to inform producers who wish to adopt tillage and rotational tactics which maximize disease establishment and minimize the impact of Canada thistle. The ecological principles developed in this study will be useful to both organic and conventional growers, and our findings have been shared with agricultural stakeholders through extension meetings, grower conferences, and virtual content. The ultimate contribution from this project is the sustainable suppression of Canada thistle infestations within agroecosystems.

The overall goal of this study is to assess the integration of the Canada thistle pathogen, Puccinia punctiformis (thistle rust) to manage Canada thistle in organic agroecosystems. 

• Research Objective 1: Assess how thistle rust responds to conventional and reduced tillage practices. 
• Research Objective 2: Compare the impacts of crop competition in rust infected Canada thistle and non-infected Canada thistle.    
• Education Objective 1: Extend knowledge of thistle rust and its integration into organic weed management.