Implications of Distribution of Propiconizole in Red Oaks on the Management of below Ground Spread of Ceratocystis fagcacearum

2005 | Dr. Jennifer Juzwik & Ryan Blaedow, USDA Forest Service and University of Minnesota

We investigated the interaction between the oak wilt pathogen (Ceratocystis fagacearum) and propiconazole in lower stems and roots of Quercus rubra to better understand published reports of fungicide failure after 2 years. Propiconazole was infused into mature oaks in July 2004 and roots were inoculated with pathogen endoconidia 1.0 m from injection sites at ±2 weeks of fungicide treatment. Pathogen presence in wood samples was determined by isolation and fungicide concentrations measured using gas chromatography-mass spectrometry. Propiconazole was detected in the roots (≤1.0 m from injection sites) of all treated trees at 2, 12, and 24 months. Propiconazole was detected in all samples (n = 68) at 2 and 12 months and in 93% of samples (n = 72) at 24 months with concentrations ranging from 815 ppm (12 months in lower stem) to 0.7 ppm (24 months in most distal root segment). Although pathogen isolation incidence was lower in treated than disease control trees at 2 and 12 months, at no time did an infused oak fail to yield the fungus upon isolation. The results document basipetal movement and degradation of propiconazole, as well as the survival of the pathogen, over time in roots and lower stems of infused red oaks.

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Year: 2005

Funding Duration: 1-3 years

Grant Program: John Z Duling

Grant Title: Implications of Distribution of Propiconizole in Red Oaks on the Management of below Ground Spread of Ceratocystis fagcacearum

Researcher: Jennifer Juzwik

Key words: propiconazole; oak wilt; preventative; root grafts; red oaks

Peer Reviewed Publications from Grant:

  • Blaedow, R.A., Juzwik, J., and Barber, B. 2010. Propiconazole distribution and effects on Ceratocystis fagacearum survival in roots of treated red oaks. Phytopathology 100:979-985. View the Publication >
  • Blaedow, R. 2009. Implications of the distribution of propiconazole in red oaks on the management of belowground spread of Ceratocystis fagacearum. Chapter 2 in: Use of the Systemic Fungicide Propiconazole for Oak Wilt Management: an Assessment of Uncharacterized Host –Pathogen-Fungicide Interactions. Ph.D. Thesis, University of Minnesota, St. Paul. View the Publication >

General Audience/Trade Publications:

  • Blaedow, R. 2010. Research update on propiconazole as an effective tool for managing oak wilt. MN Turf & Grounds Foundation: Clippings, Fall/Winter 2010:6-9. View the Publication >

Presentations: none

For more information on this project, contact the researcher via TREE Fund at