In southwest Oregon, an aggressive program of cutting and burning host plants in an effort to eradicate Phytophthora ramorum was begun in 2001. It was soon apparent that tanoak (Lithocarpus densiflorus) resprouts were highly susceptible to P. ramorum and that infected sprouts hamper eradication efforts by maintaining inoculum on site.
The basidiomycete fungus Chondrostereum purpureum causes a white rot of mostly broadleaf trees and has a wide host range. It involves through fresh wounds in the xylem or cut stumps and is a weak pathogen that can survive as a saprophyte. After the host tree is weakened or killed, C. purpureum is quickly replaced by other, more competitive decay fungi that are naturally occurring in the environment. This fungus is used as a biological control for woody vegetation all over the world.
A preparation of mycelium of the fungus C. purpureum is registered under the trade name “Chontrol™ Paste” in the US and Canada for use as a biological control agent and has been tested as a stump treatment on many hardwood species (EPA Registration No. 74200-1, 2004; and PMRA Registration No. REG. 2004-09, 2004). Treatment of stumps with C. purpureum has been shown to be effective for suppression of resprouting on several species, most notably red alder (Alnus rubra).
In Fall 2010, our research team established field trials near Brookings, Oregon to assess the bioherbicidal efficacy of C. purpureum on tanoak to inhibit resprouts, which can harbor P. ramorum and serve as a source of inoculum. Early results showed that C. purpureum was able to colonize the stumps of tanoak following treatment.
Research is underway to test various decay fungi such as C. purpureum and Ganoderma spp. on California bay laurel (Umbellularia californica) prior to field testing in California.
Publications
Biological control of tanoak resprouts using the fungus Chondrostereum purpureum (pdf) Marianne Elliott, Simon Shamoun, Grace Sumampong, Ellen Goheen, Alan Kanaskie, and Gary Chastagner. Poster presented at 59th WIFDWC, October 2011.
WSU Puyallup Research & Extension Center
2606 West Pioneer, Puyallup, WA, 98371-4998 USA
Last updated 9/24/2025