Canada Thistle Management in CRP Demonstration Plots Provides Statewide & Nationwide Education

Jim Fawcett, Extension Field Agronomist, Southeast Area

Problem Statement:

Canada thistle continues to be one of the most persistent weed problems on CRP ground and in pastures. The above ground portion of the plant is easy to kill, but because of its extensive underground root system, long-term control is difficult. This makes it more difficult for homeowners and crop producers to understand which control techniques are most effective.

Programmatic Response:

With funding from DOW, Canada thistle control plots were put out in the spring of 2006 on CRP ground in Johnson County to demonstrate products which are and are not effective in the long-term control of Canada thistle. A tour was conducted one year after the application of the herbicides so attendees could see which products gave the best long-term control. The date of the tour was chosen to coincide with the best time to apply the herbicides so people could put their education immediately to work. Results of the research, along with results from a similar trial in Keokuk County in 2004, were presented at the Weed Science Society of America conference in San Antonio, TX. The demonstration involved cooperation with industry, DNR, NRCS, and ISU Extension. A fact sheet based on the results of the trial was sent out to other field agronomists and the results were also discussed at winter pesticide applicator and crop advantage meetings.


Despite threatening weather, 50 attended the tour, with some driving over 50 miles to attend. There was considerable discussion among the attendees on weed management in CRP and other CRP issues, with the discussion lasting after dusk. Several commented on the timeliness of the information. The local research helped to increase the interest of the audience at private pesticide applicator sessions.

April 25, 2008

106 Conservation Reserve Program Alternatives

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