I noticed some Ailanthus trees dead by the side of the highway, and wrote asking my local paper what was up with them – was the highway department killing them?  They actually wrote an article about it –


Of course he mispelled basal bark treatment and neglected to mention triclopyr, the herbicide used (mentioned elsewhere in this blog).  But those problems are easily forgiven, with the note about “nonalfalfae”, a natural occuring fungus that is killing the trees.  And that it has been found at milepost 125 on I81, which is exactly where I saw the dead trees.  Poking around on the interwebs, I found that this was the very first place that this was discovered in VA. I’m sure it was noticed there, as it is close to VA Tech.

Further poking around finds that the fungus is actually called Verticillium nonalfalfae.  In a scientific article published only a couple of weeks ago by VA Tech and University of PA researchers, in the field, 100 canopy Ailanthus trees were inoculated across 12 stands with VnAa140 (verticillium nonalfalfae) from 2006 to 2009. By 2011, natural spread of the fungus had resulted in the mortality of >14,000 additional canopy Ailanthus, 10,000 to 15,000 Ailanthus sprouts, and nearly complete eradication of Ailanthus from several smaller inoculated stands, with the exception of a few scattered vegetative sprouts that persisted in the understory for several years before succumbing.

The article concludes: Our results indicate that V. nonalfalfae is host-adapted and highly efficacious against Ailanthus and is thus a strong candidate for use as a biocontrol agent.  I’ve written to the VA Tech researcher to see if I can get the fungus to innoculate some trees here.

So, like rose-rosette disease killing off the invasive multlflora, we now have potential biocontrol of ailanthus.  Next up, something for autumn olive?