To combat tree fungus on poplar trees, remove dead or diseased poplar branches to keep the fungus from spreading. Apply a fungicide, such as Daconil or Ortho Multi Purpose Fungicide, to the root system. Follow label instructions, and apply every one to two weeks during the growing season.
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Kenneth Black has been a freelance writer since 2008. He currently works as a staff writer for "The Times Republican" in Central Iowa. He has written extensively on a variety of topics, including business, politics, family life and travel. Black holds a bachelor's degree in business marketing from the University of Phoenix.