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United States Department of Agriculture

Agricultural Research Service

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Research Project: IMPLEMENTING SUCCESSFUL BIOLOGICAL CONTROL OF CANADA THISTLE WITH A HIGHLY SPECIFIC RUST FUNGUS WIDELY ESTABLISHED IN NORTH AMERICA

Location: Foreign Disease-Weed Science

Project Number: 8044-22000-039-04
Project Type: Reimbursable

Start Date: Oct 01, 2007
End Date: Aug 31, 2012

Objective:
The objectives of this research are to: 1) demonstrate the ability of Canada thistle seedlings, systemically diseased with the rust fungus Puccinia punctiformis, to reduce thistle density and provide sustainable biological control, 2) implement successful biological control of Canada thistle on a relatively large scale, and 3) provide land managers with the techniques to mass produce systemically diseased seedlings, introduce them into thistle patches, and effectively manage the patches to optimize biological control with the rust fungus and expand areas under control.

Approach:
Canada thistle seedlings systemically diseased with the rust fungus, P. punctiformis, will be produced in greenhouses in either Ft. Detrick (for use in Maryland) or at Pennsylvania State University (for use in Pennsylvania). Diseased seedlings will be produced using teliospores of the fungus collected from the state of intended use, and seedlings will be transplanted to healthy patches in April. Either 0, 2, 4, or 6 systemically diseased seedlings will be established per each patch with one inoculum level per patch. At each inoculum level, half the number of the patches will be mowed and the other half left un-mowed. Procedures for producing systemically diseased seedlings will be transferred to stakeholders. We plan on locating and using 96 Canada thistle patches in 12 field sites, with about half of the sites in Maryland and half in Pennsylvania. A minimum of ten healthy thistle patches will be used for each field site. Stakeholders in charge of sites will mow or arrange to mow half of the patches in these sites. Data from each patch will be collected each year in June - July. Dependent variables will be: healthy Canada thistle density, diseased shoot density, and patch diameter. Data collection will be done by student interns under the supervision of a graduate student at Pennsylvania State University.

Last Modified: 12/22/2014
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